Four major diseases of chili pepper including two fungal diseases, anthracnose (Colletotrichum acutatum) and Phytophthora blight (Phytophthora capsici), and two bacterial diseases, bacterial wilt (Ralstonia solanacearum) and bacterial spot (Xanthomonas campestris pv. vesicatoria), were investigated under future climatechange condition treatments in growth chambers. Treatments with elevated CO2 and temperature were maintained at 720 ppm±20 ppm CO2 and 30oC±0.5oC, whereas ambient conditions were maintained at 420 ppm±20 ppm CO2 and 25oC±0.5oC. Pepper seedlings or fruits were infected with each pathogen, and then the disease progress was evaluated in the growth chambers. According to paired t-test analyses, bacterial wilt and spot diseases significantly increased by 24% ( p=0.008) and 25% ( p=0.016), respectively, with elevated CO2 and temperature conditions. On the other hand, neither Phytophthora blight ( p=0.906) nor anthracnose ( p= 0.125) was statistically significant. The elevated CO2 and temperature accelerated the progress of bacterial wilt by two days and bacterial spot by one day compared to the ambient treatment. Temperature regime studies of the diseases without changes in CO2 confirmed that the accelerated bacterial disease progress was mainly due to the increased temperature rather than the elevated CO2 conditions.