BACKGROUND: Aging process causes several changes in the typical sleep patterns. Elderly people complain frequently about sleep duration, changes of sleep/wake rhythm and day time sleepiness. This study was performed to evaluate improvement of sleep quality after laughter therapy. METHODS: On July 2007, the study participants aged over 65 were recruited through a community center in Daegu. There were 48 subjects in the experimental group and 61 in the control group. The laughter therapy program was applied to the experimental group. We compared Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) before and after laughter therapy. Data were analyzed by independent t-test, chi-square test, paired t-test, and ANCOVA using SPSS windows ver. 14.0. RESULTS: At initial study, there were no significant differences in baseline characteristics. The ISI scores were 8.00 +/- 6.29 and 8.36 +/- 6.38; the PSQI scores were 6.98 +/- 3.41 and 7.38 +/- 3.70; The Geriatric Depression Seals (GDS) scores were 7.98 +/- 3.58 and 8.08 +/- 3.95 in experimental and control groups, respectively. After laughter therapy, the ISI scores were 7.58 +/- 5.38 (P = 0.327) and 9.31 +/- 6.35 (P = 0.019), PSQI scores were 6.04 +/- 2.35 (P = 0.019) and 7.30 +/- 3.74 (P = 0.847), GDS scores were 6.94 +/- 3.19 (P = 0.027), 8.43 +/- 3.44 (P = 0.422) in experimental and control groups, respectively. CONCLUSION: The laughter therapy is considered to be useful for the elderly people in a community that improves insomnia and sleep quality.