METHODS: This two-group randomized clinical trial was conducted on 69 cancer patients undergoing chemotherapy at the Reza Chemotherapy and Oncology Center, Mashhad, Iran, in 2018. Patients were randomly divided into intervention and control groups. Both groups received routine self-care training, with the addition of four 20-min to 30-min laughter yoga sessions held immediately before one of their chemotherapy appointments for the intervention group only. Nausea and vomiting were assessed using the Morrow Assessment of Nausea and Emesis questionnaire at two stages, before and after the intervention. Data were analyzed with Chi-square, Independent-t, Mann-Whitney, Wilcoxon, and McNemar tests using Statistical Package for the Social Sciences (SPSS).