The striped catfish, Pangasianodon hypophthalmus is a facultative air-breathing fish. This species is widely cultured in the freshwater areas of the Mekong Delta, Vietnam. This study reports the effects of elevated temperatures, carbon dioxide (CO2) concentrations, and the combination of CO2 with different temperatures on embryonic development, fertilization, and hatching. The first experiment included four temperatures (27, 30, 33, and 36ºC); the second experiment consisted of four concentrations of CO2 (0.7±0.02, 7.05±0.22, 14.2±0.6 and 21.4±0.3 mmHg CO2), and the third one was the combination of CO2 and temperatures with five treatments including the temperature and CO2 ≤ 0.7 mmHg) (control), 7 mmHg CO2 at two temperatures (27 and 33ºC) and 14 mmHg CO2 at two temperatures (27ºC and 33ºC). The fertilized eggs from artificial breeding were directly exposed to the tested treatments. The results show that the hatching rate of eggs (62.3%) was highest at 30ºC, and the time spent to complete embryonic development (20.2 hours) was shortest at 33ºC. The increase in CO2 concentrations in the water did not affect the fertilization rate (p > 0.05), but the hatching rate decreased with the increased CO2 concentrations. The embryonic development was significantly affected by high CO2 concentrations at elevated temperatures. Particularly, the lowest hatching rate (40.8%) and the longest time for embryonic development (approximately 25.5 hours) were found in the treatment of 14 mmHg CO2 at 33ºC. It is summarized that the increase in temperature combined with a high concentration of CO2 in water affects the embryonic development of striped catfish.