© 2017 Springer Science+Business Media, LLC Osteoarthritis is a degenerative joint disease in which interleukin-1β plays a major role in the inflammatory process. Administration of collagen hydrolysate was an optional treatment of osteoarthritis. Fish has become an interesting source of collagen hydrolysate because of religious reason and there is no risk from mad cow disease. However, the effects of different sizes of fish collagen hydrolysate on cartilage and chondrocyte metabolism have not been well studied yet. This study examined the effect of different sizes of fish collagen hydrolysate on cartilage metabolism. Three different sizes of fish collagen hydrolysate were prepared by size exclusion using centrifugation, which composed of small fraction ( < 3 kDa), medium fraction (3–10 kDa) and large fraction ( > 10 kDa). Using porcine cartilage explant, in physiological condition, all the three fractions had no effect on cartilage metabolism, but they could induce pro-MMP3 and pro-MMP13 secretions through activation of p-ERK and p-p38. In pathological condition induced by interleukin-1β and oncostatin-M, small and medium fractions showed additive effect with interleukin-1β and oncostatin-M on cartilage degradation, whereas large size had no effect. In addition, the effect of small size occurred through further activation of p-p65, which resulted in further induction of active-MMP13, while medium size had a different mechanism. In conclusion, all three fractions fish collagen hydrolysate had no effect on cartilage metabolism in physiological condition, but small and medium fractions had adverse effect on cartilage in pathological condition. Taken together, various sizes of fish collagen hydrolysate showed different effects on cartilage metabolism. Therefore, different sizes of fish collagen hydrolysates play different roles on cartilage metabolism, especially in the pathological condition.