To find the optimal eggs to larvae transforming temperature of walleye pollock Theragra chalcogramma, we investigated their hatching pattern, mortality, and larval deformities. Results showed that the hatching quality decreased as the water temperature increased and dropped sharply above 13°C. The highest hatching rate was achieved at 7°C, whereas the lowest was at 15°C. Dead eggs were not observed at 7°C; however, dead egg ratios were significantly high at 4.5°C and above 13°C (P<0.05). Mortality of larvae after hatching was not observed at 4.5°C, but was significantly high above 13°C. The DNA content of the larvae did not show any significant difference at all water temperatures; however, RNA content was the highest at 7°C and was significantly low above 11°C. In addition, RNA/DNA ratio was the highest at 7°C. Larval deformities after hatching were low at 7-11°C and higher at higher or lower water temperature. Therefore, the hatching index and larval health index of Walleye pollock eggs in this study show that 7°C to 11°C seems to be the optimal transforming water temperature range.