Effects of seven artificial diets with varying protein, carbohydrate and tannic acid contents on the survival of Vanessa atalanta larvae infected by Bacillus thuringiensis subsp. kurstaki (Btk) were studied. The highest survival rate among the infected larvae was observed from the group feeding on diet containing 10% of tannic acid. The highest mortality rate was observed among the larvae feeding on artificial diet with the lowest protein amount. Maximum mortality in each diet group was observed on the third day among the larvae infected by bacteria. This mortality was particularly higher among the larvae feeding on diet that contain less amount of protein. Among the infected larvae, the highest number of total haemocytes was found among those that fed on diet containing 2.5% of tannic acid. The lowest number of haemocytes was found in larvae that fed on diet with lower protein amount. The lowest pupal protein amount was found among the infected larvae feeding on artificial diet containing much lower amounts of protein.