The purpose behind this study is to determine the effects of Laughter Therapy on fatigue and depression in cancer patients undergoing chemotherapy. The study is a random clinical trial by throwing a coin in two groups of Intervention and Control. Laughter therapy program includes comedy and funny movies, and lively programs. Intervention group is 8 sessions for each session to be between 25 to 30 minutes in 8 weeks. And Control group enjoys only the usual cares. The main criteria for inclusion in the study include having the age of 18 to 55, being on the list of chemotherapy patients, and lack of known depression disorder. The main criteria for exclusion from the study are Lack of desire for continuing, and having depression score over 28 using Beck Questionnaire. Therefore, the total sample size in this study is 90 samples from which 45 patients are in Intervention group and 45 patients in Control group. Before the beginning of intervention, the questionnaire will be given to the samples. Then, at end of the second, fourth, sixth and eighth week in the Intervention group, a quiz is taken from the samples and they are asked to complete Beck Depression Questionnaire and CFS Questionnaire; after that, again, Fatigue Questionnaire and Beck Depression Questionnaire will be given to them. Finally, a month passed the last session Laughter Therapy will begin.