The vast majority of Americans do not engage in adequate regular physical activity despite its well-known health benefits. Even when individuals attempt to become more active by joining a fitness center, estimates suggest that nearly half terminate their membership within the first 6 months. A better understanding of who is at risk for early membership termination upon joining may help researchers develop targeted interventions to improve the likelihood that individuals will successfully maintain memberships and physical activity. This study's purpose was to identify, based on a wellness assessment (WA) used in fitness centers, individuals at risk for fitness membership termination prior to 1-year. Center members (N = 441; Mage = 41.9, SD = 13.1; 74.4% female) completed a comprehensive WA of stress, life satisfaction, physical fitness, metabolic health, and sleep quality at the beginning of their memberships and were followed for one year. Latent class analyses utilized the WA to identify four groups: (a) healthy, (b) unhealthy, (c) poor psychological wellness, and (d) poor physical wellness. Participants in the poor psychological wellness group (OR = 2.24, p = 0.007) and the unhealthy group (OR = 2.40, p = 0.037) were significantly more likely to terminate their memberships at 1-year as compared to the healthy group. Participants with poor physical wellness visited the fitness center less frequently than healthy participants (p < 0.01). Results suggest that poor psychological wellness is a risk factor for terminating memberships, whereas poor physical wellness is not. Future studies should replicate these latent classes and develop targeted interventions to address psychological wellness as a method to improve fitness membership retention.