From 2027, L4 only for one insurance title.

A doctor will no longer issue sick leave for all activities at once if the illness allows one of them to be performed. This is the final stage of the L4 reform. Small companies will be able to check sick leave on their own as early as April.

From January 1, 2027, a doctor will be able to issue a sick leave certificate (L4) only for one insurance title, according to pulsHR.pl. A person employed full-time who also works under a mandate contract for another company will receive L4 only for one of these jobs if their health condition allows them to perform the other one. Until now, incapacity for work covered all places of employment.

The change results from the Act of December 18, 2025 amending the Act on the social insurance system and certain other acts. The President signed it on January 7, 2026. According to Infor.pl, the regulations come into force in three stages: January 27, 2026, April 13, 2026, and January 1, 2027.

From April 13, employers with no more than 20 employees may themselves check whether an employee on sick leave is not doing paid work and is not doing anything contrary to the purpose of the leave, reports “Rzeczpospolita”. Previously, they had to ask the Social Insurance Institution (ZUS) to carry out an inspection and had no influence over its timing or course.

The inspector must present written authorization, and a report is prepared for each inspection, including when no violations are found. The final decision still belongs to ZUS. The employer pays sick pay for the first 33 days of leave, and in the case of employees over 50 years of age, for 14 days.

From 2026, a new definition of paid work also applies: it is any activity that generates income. For such activity, just like for actions contrary to the purpose of the leave, an employee may lose sickness benefit for the entire period of L4. This does not apply to minor matters, such as answering a phone call or replying to a work email. An exception also applies to single activities performed due to important, exceptional circumstances, but an employer’s work instruction is not included among them.

For companies cooperating with people working under several contracts, this means that from January 2027, an employee for whom a doctor issues L4 only for one job will be able to continue working legally for another employer.