Frailty is a major geriatric problem leading to an increased risk of disability and death. Prevention, identification, and treatment of frailty are important challenges in gerontology and public health. The study aimed to estimate the prevalence of the frailty phenotype (FP) among the oldest-old Polish Caucasians and investigate the relationship between the FP and mortality. Baseline data were collected from 289 long-lived individuals, including 87 centenarians and 202 subjects aged 94-99. Mortality was obtained from population registers over the following 5 years. Sixty percent of subjects were classified as frail, 33% as prefrail, and 7% as robust. Frailty was more common in women than men and among centenarians than nonagenarians. During the 5-year observation period, 92.6% of the frail women and all frail men died, while mortality rates were lower among prefrail, 78.8% and 66.7%, and robust individuals, 60% and 54.5%, respectively. In the survival analysis, frailty was the strongest negative risk factor: HR = 0.328 (95% CI: 0.200-0.539). The inability to perform handgrip strength measurement was an additional predictor of short survival. In conclusion, the FP is prevalent in nonagenarians and centenarians and correlates with lower survivability. Future studies should address differences between unavoidable age-associated frailty and reversible disability in long-lived individuals.