BACKGROUND: The relationship between different weight class and mortality risk remained uncertain in cervical cancer patients. Thus, we conducted the study to assess the association between different body weight classes and survival outcomes in patients with cervical cancer. METHODS: This was a retrospective cohort study including 6908 cervical cancer patients from the Taiwan Cancer Registry database. A COX regression model was used to evaluate the relationship between different weight classes and time-to-event outcomes of overall survival and cancer-specific survival at three years. RESULTS: The median follow-up time was 4.64 ± 2.55 years. Our study revealed that the underweight group had a significantly higher risk of overall death [hazard ratio (HR) = 1.65, 95 % confidence interval (CI) = 1.37, 1.99] than the normal-weight group. Overweight patients had a significantly lower risk of overall death (HR = 0.81, 95 % CI = 0.71, 0.93), whereas the obesity group had an insignificant lower risk of overall death (HR = 0.92, 95 % CI = 0.75, 1.13) compared with the reference group. CONCLUSION: After controlling for confounding factors, underweight patients with cervical cancer had a higher risk of overall death than normal-weight patients with cervical cancer. Our study indicates that underweight cervical cancer patients had a higher risk of overall death compared with normal-weight cervical cancer patients. Furthermore, the overweight patients had a significantly lower risk of overall death. More strategies are needed to be addressed especially in public health field regarding women's weight class and cancer mortality issues.