While relatively few countries have changed their working time legislation in recent years, new working time patterns show some changes in approaches to night and shiftwork. Prominent trends include (i) the spread of irregular hours of work to different sectors, including services, often as a result of decoupling business hours from individual working hours; (ii) greater flexibility, often in return for shorter hours, in covering operating hours by different individuals; (iii) the appearance of complex combinations of different categories of working time arrangements, such as a combination of full-time semi-continuous shifts and part-time weekend shifts; and (iv) the adoption of a complex process for changes in schemes, incorporating group study and joint planning. Importantly, these trends reflect fundamental changes in the concept of night work (and that of nightworkers). The issues related to these recent trends were apparent in the two-year debate that led to new international labour standards, the Night Work Convention (No. 171) and Recommendation (No. 178), 1990, both of which apply to both sexes and to nearly all occupations. Also adopted was the Protocol of 1990 to the Night Work (Women) Convention (No. 89) of 1948, under which national laws or regulations may now permit night work of women in industry under strictly defined conditions. The new Convention and Recommendation define 'nightworker' to include workers performing a substantial amount of night work. They prescribe a variety of actions to improve the quality of working life of such workers, including measures related to working hours, rest periods, safety and health, transfer to day work, maternity protection, social services, and consultations. Strategies should be adopted that take into account the local situation, that are participatory, and that take due account of the diverse aspects of working life associated with the new concept of night work.