The aim of this study was to investigate the oxygen binding properties of the turbot (Scophthalmus maximus) hemoglobin polymorphism with special references to pH and temperature. Hemolysate samples from the three hemoglobin genotypes Hb- I(1/1), Hb-I(1/2) and Hb-I(2/2), were tested at 10, 16 and 19 °C and at pH values 7.2, 7.5 and 7.8 at 100 mm NaCl respectively. Hb-I(2/2) had the highest oxygen affinity at all three temperatures followed by Hb- I(1/2) and Hb-I(1/1). There was a significant decrease in oxygen affinity with increasing temperature and increasing pH in the range 10 to 19 °C for all three genotypes. The genotype Hb-I(1/1) had the highest Bohr effect followed by genotype Hb-I(2/2) and Hb-I(1/2). The effect was highest at 10 °C and decreased with temperature. Temperature sensitivity of the O2 binding for turbot hemoglobin was low and increased in general with increasing pH. It is hypothesised that the low sensitivity hemoglobins may be an adaptation to variable temperature conditions in the distribution area of the species.