Karōshi: Japan's word for death from overwork

Karōshi (過労死) is Japanese for "death from overwork". Japanese law uses the word for death from a stroke or heart disease caused by too much work. It also covers death by suicide linked to a mental illness from heavy work stress. Since 2014, a national law has told the government to prevent it.

You may be here because someone you love died, and you think work played a part. Or you may be the one working too much. Either way, this page explains the word, the law and your rights in plain words.

What does karōshi mean?

The word has three parts. Ka (過) means "too much". Rō (労) means "work". Shi (死) means "death".

Japan's 2014 law gives the legal meaning. In the government's own English, karōshi covers three things:

• death from a stroke or heart disease brought on by too much work;
• death by suicide linked to a mental illness, when that illness came from heavy stress at work;
• the same illnesses, when the person survives.

The second kind has its own name, karōjisatsu (過労自殺). A Japanese lawyer made the term widely known in 1998.

Where does the word karōshi come from?

A doctor, Tetsunojo Uehata, and his colleagues first used the word in 1978. They described 17 cases at a meeting of the Japan Society for Occupational Health.

In 1982, Uehata and two colleagues wrote a book about karōshi. It explained how to judge if a stroke or heart attack came from work.

In 1988, lawyers and doctors started "Karōshi 110", a phone service for families. It began in Osaka in April and went national in June. Families shared their stories, and the word spread.

Today, researchers say karōshi has become a word used far beyond Japan.

What does Japan's karōshi law say?

The Act on Promotion of Measures to Prevent Karoshi (過労死等防止対策推進法) is Act No. 100 of 2014. It was published on 27 June 2014. It came into force on 1 November 2014.

The law does three main things:

1. It gives karōshi a legal meaning (Article 2).
2. It makes November "Karōshi Prevention Month" every year (Article 5).
3. It makes the government report to parliament every year (Article 6). This report is the White Paper on karōshi.

The newest White Paper is the 2026 edition. The Cabinet approved it on 9 October 2026. It is the 11th edition. An English summary of the 2025 edition is also free to read.

How many karōshi claims are there each year?

Every year, Japan's Ministry of Health, Labour and Welfare (MHLW) publishes the numbers. These are for the year from April 2025 to March 2026. They were published on 15 July 2026.

Fiscal year 2025 (Apr 2025 to Mar 2026)	Claims made	Claims approved	Source
Stroke and heart disease	1,254	217	MHLW, 15 Jul 2026
Of these, deaths	303	67	MHLW, 15 Jul 2026
Mental illness caused by work	4,958	1,082	MHLW, 15 Jul 2026
Of these, suicide or suicide attempt	215	76	MHLW, 15 Jul 2026

Claims for stroke and heart disease rose by 224 from the year before. Claims for mental illness rose by 1,178.

The most common cause in approved mental illness claims was power harassment, with 222 cases. Power harassment means bullying by a boss or someone with more power.

These numbers only count claims made to the government. They cannot show every person harmed by work.

When does Japan count a death as caused by overwork?

For a stroke or heart disease, MHLW looks at overtime. Here, overtime means hours above 40 a week. It looks at about six months before the illness.

Overtime per month (above 40 hours a week)	How MHLW judges the link to work	Source
Never more than about 45 hours	Weak link	MHLW criteria, 2021
More than about 45 hours	The link grows as hours grow	MHLW criteria, 2021
About 100 hours in the month before the illness	Strong link	MHLW criteria, 2021
More than about 80 hours a month, on average, over 2 to 6 months	Strong link	MHLW criteria, 2021

In September 2021, MHLW made the rules fairer. Hours close to these limits can now count too. This happens when other kinds of strain were also present. Examples are:

• short rest between shifts (less than about 11 hours);
• work that is hard on the body;
• many days in a row with no day off;
• irregular hours, shift work or late-night work.

A very heavy week can also count. MHLW looks at about one week before the illness for this.

What about mental illness caused by work?

MHLW has separate rules for mental illness. They were updated on 1 September 2023. The update added customer harassment. This means serious abuse from customers or clients.

If work stress caused a mental illness, a later death by suicide can be recognised as work-related. This is a rule about compensation.

In real life, suicide is never caused by work alone. WHO says the reasons are "multi-faceted". Most people with heavy work stress do not become suicidal. Help works, and the lines at the top of this page are free.

What is Japan's legal limit on overtime?

Since 2019, Japan has a legal cap on overtime. It came with the "Work Style Reform" (働き方改革).

Overtime rule in Japan	Limit	Source
Normal limit	45 hours a month and 360 hours a year	MHLW guide
Highest limit, with a special agreement	720 hours a year	MHLW guide
Overtime plus holiday work, any one month	Less than 100 hours	MHLW guide
Overtime plus holiday work, average over 2 to 6 months	80 hours or less	MHLW guide
Months a year above 45 hours	6 at most	MHLW guide

Notice that the 80 and 100 hour limits match the compensation rules above.

The cap started for large companies in April 2019, and smaller ones in April 2020. Construction, drivers and doctors joined in April 2024, with some special rules.

How does a family claim workers' compensation for karōshi?

Workers' compensation (労災保険, rōsai hoken) pays families when a death is caused by work. You do not need a lawyer to claim. But many families find one helps.

1. Collect proof of the hours. Look for time cards, computer log-in times, emails, work chat messages and shift plans. Ask colleagues what they saw.
2. Keep the medical records. These include the death certificate and any hospital notes.
3. Send the claim. Send it to the head of the Labour Standards Inspection Office (労働基準監督署) that covers the workplace. Survivors' pension uses Form 12 (様式第12号).
4. Watch the time limits. MHLW sets these deadlines:

What you can claim	Deadline	Source
Survivors' pension or lump sum (遺族補償給付)	5 years from the day after the death	MHLW Q&A
Funeral costs (葬祭料)	2 years from the day after the death	MHLW Q&A

If the work records are hard to get, do not give up. Write down what you remember now, while it is fresh.

Where can you get help in Japan?

• Working conditions hotline (労働条件相談ほっとライン): call 0120-811-610. It is free and anonymous, in 13 languages. The English line is 0120-531-401. Weekdays 5pm to 10pm; weekends and holidays 9am to 9pm (MHLW).
• Kokoro no Mimi (こころの耳): MHLW's mental health line for workers. Call 0120-565-455. Weekdays 5pm to 10pm; weekends 10am to 4pm (MHLW). If your number is hidden, dial 186 first. There is also LINE chat.
• Lawyers for karōshi families: the National Defense Counsel for Victims of Karoshi (過労死弁護団全国連絡会議) is a network of lawyers. Their website is karoshi.jp.
• Other families: the National Family Association of Karoshi (全国過労死を考える家族の会) brings families together.

If you are struggling to cope, the crisis lines at the top of this page are free. You can call any time.

What can you do today?

If you are working long hours, start a simple diary of your hours tonight. See a doctor if your body feels wrong. Our guide to overwork warning signs and your rights can help.

If you lost someone, be gentle with yourself. Grief and anger can come together. You do not have to sort out everything at once. One phone call is enough for today.