Studies were conducted in four regions of central Greece (Larisa, Karditsa, Livadia, Thiva), to evaluate the productivity and fibre properties (fibre strength and fibre length) of the five most commonly grown cotton cultivars in these regions. The experiments lasted for 6 years (1995)(1996)(1997)(1998)(1999)(2000). All the characteristics tested were strongly influenced by the factors ÔyearÕ, ÔcultivarÕ and ÔregionÕ. Significant cultivar · region, year · cultivar, region · year and cultivar · region · year interactions occurred for all the characteristics studied. The cultivar Alegria had the highest seed-cotton and lint yield, while Aria had the lowest ones. Both cultivars gave the highest mean lint percentage but the lowest mean boll weight (MBW). Alegria had the lowest fibre strength, while Aria had the highest. The Acala-type cultivars, Acala SJ2 and Zeta 2, had intermediate seedcotton and lint yield, while Vered 171 had high seed-cotton and satisfactory lint yield. The three cultivars mentioned above had the highest MBW and very good fibre strength. Positive correlation was observed between fibre strength and length. In spite of the fact that mean fibre length was statistically the same in all cultivars, it was influenced by the factor ÔyearÕ, as a result of different weather conditions. The year 1996 was the most unfavourable one for seedcotton yield and MBW, because it was characterized by lower than average air temperatures and rather dry conditions for all study sites. The factor ÔregionÕ, a combination of different climatic conditions and cultural practices, influenced significantly all the parameters studied.