Background: Experiencing painful procedures during life is inevitable. Poor pain management is associated with negative effects on the quality of life, remaining for a long time after the experience. Long-term negative effects of pain possess a significant cost burden on society. Nowadays, computers are globally available, and computerized psychological interventions can reduce negative emotions. Objectives: The present study aimed at examining the effectiveness of conventional cognitive-behavioral therapy (CBT) and its computerized version on reduction in pain intensity, depression, anger, and anxiety in children with cancer. Methods: The present randomized, controlled, clinical trial was performed on three groups of conventional CBT, computerized CBT (cCBT), and control. Children with cancer, referring to Shafa Hospital of Ahvaz, Iran, constituted the study samples. A total of 15 children aged 9 - 12 years were assigned to each group by using the lottery method. All three groups received routine medical treatments during the study, but the two intervention groups also received psychological interventions as a complementary treatment. The control group received routine medical treatment and underwent cCBT intervention after the study. The data-i e, pre- and post-tests, were collected by a masters’ student in clinical psychology that was blind to the study objectives. Data were analyzed by MANCOVA, ANOVA, and t-tests of differential scores. Results: The findings of the study indicated that both interventions could reduce negative emotions associated with cancer (i. e, pain, anger, anxiety, and depression) in children compared with the control group (P < 0.0001). In addition, there were no significant differences between the two intervention groups (P < 0.01). It means both interventions were useful to reduce pain and enhance adjustment. Conclusions: The cCBT can be utilized in case of no access to psychologists and psychological services.