Objectives The objective of the study was to investigate the associations of a nine-point body condition score (BCS) with survival time and lifespan in cats. Methods Electronic patient records from a cat-dominant primary practice in metropolitan Sydney, Australia, where the body condition of cats was regularly recorded using a nine-point BCS scale were obtained. The maximum BCS of each cat during the visits was used as the primary exposure variable. Two survival analyses were conducted to evaluate the associations of BCS with cats’ survival and lifespan. Results In total, 2609 cats met the selection criteria from 4020 cats screened. The median of the maximum BCS was 6 (interquartile range [IQR] 5–7). Compared with cats with a maximum BCS of 6, increased hazards of death were observed in cats with a maximum BCS of 3 (hazard ratio [HR] 4.67, 95% confidence interval [CI] 3.00–7.27), 4 (HR 2.61, 95% CI 1.95–3.49), 5 (HR 1.43, 95% CI 11.5–1.76) and 9 (HR 1.80, 95% CI 1.11–2.93). Median lifespan was 15.8 (IQR 13.5–17.6) years. Compared with cats reaching a maximum BCS of 6 in the same age group, cats reaching a maximum BCS of 4 (HR 4.15, 95% CI 1.26–13.67) or 5 (HR 1.75, 95% CI 1.07–2.85) between age 1 and 3 years, and a maximum BCS of 3 (HR 6.09, 95% CI 1.47–25.25) and 9 (HR 2.27, 95% CI 1.27–4.04) between the age of 3 and 11 years had shorter lifespans. Conclusions and relevance There are significant associations of nine-point body condition scoring with survival and lifespan, and BCSs <5 and of 9 were found to be negatively associated with both. The study yielded information regarding a desirable BCS for cat longevity that veterinarians could consult with.