This study analyses the structural, technological performance components and the overall productivity of inland rainbow trout ( Oncorhynchus mykiss) farms in the Marmara region, Turkey. Of 81 active farms, 36 were small scale (1-10 t year(-1)), 32 medium-sized (11-30 t year(-1)) and 13 large production units ( over 30 t year(-1)). Sufficient data for this study were collected from 70 farms for inclusion in the analyses; 59.3% were so-called combined farms ( hatchery and grow-out), 37.9% on-growing farms ( for market production) and 2.9% producing juvenile fish only for stocking or for supply to grow-out farms. Juvenile fish production was largely conducted on large farms. Capacity utilization (102.8%) of the large farms was most similar to their projected capacity. Many large farms (43.9%) use high-tech utilities and tools. Small farms mostly use concrete ponds whereas most medium and large-scale farms use fiberglass tanks. Medium and large-scale farms were found to be more successful in broodstock management, fertilization, hatching success and survival rate of juvenile fish. Fish stocking density in medium-sized farms (21.8 kg m(-3)) was higher than in small-scale (14.5 kg m(-3)) and large-scale farms (15.5 kg m(-3)). Overall feed conversion ratio for all farms was estimated as 1.2. From the survey results it appears that production capacity planning was calculated more accurately in the projection phase for small and large-scale farms rather than for medium-sized farms. Medium and large-scale farms were more successful in terms of performance ( good experience, good structural and technological capabilities).