PURPOSE: Purpose of this study was to investigate relationships and influence of peripheral neuropathy, sleep, and quality of life in patients with gastric cancer who are receiving chemotherapy. METHODS: Participants were 131 patients with gastric cancer being treated at a chemotherapy outpatient clinic and receiving chemotherapy. Data were analyzed using descriptive statistics, t-test, ANOVA, and multiple regression analysis with the SPSS program. RESULTS: Mean score for peripheral neuropathy was 24.66, for sleep, 6.71 and for quality of life, 67.69. Peripheral neuropathy had a significant positive correlation with sleep (r=.26, p=.003) and sleep had a significant negative correlation with quality of life (r=−.50, p < .001). The regression model explaining quality of patients' lives was significant (F=11.91, p < .001), peripheral neuropathy, sleep, and pain due to anticancer drugs and number ofneurotoxic anticancer drugs explained 25.1% of the variance in quality of life and sleep was the most important factor. CONCLUSION: To improve the quality of life for these patients, individualized nursing interventions for pain should be provided according to number of anticancer drugs in the chemotherapy. Also there is a need to identify ways to assess peripheral neuropathy and sleep disorders that are appropriate in the treatment and reduce side effects during treatment.