Purpose. The purpose of this investigation was to develop and validate a one-repetition maximum (1-RM) prediction model for the upper and the lower body in non-resistance trained women. Methods. Sixty seven healthy, non-resistance trained women between the ages of 18 and 25 years volunteered for this investigation. The investigation was performed in 2 phases. During phase I, all subjects completed 2 experimental sessions. During the first session, subjects performed a bench press repetition to fatigue (RTF) test with 45 lb and 55 lb. Subjects also performed a leg press RTF with 175 lb and 215 lb. Additional variables that were measured were: body height (in.), body weight (lb), and sum of skinfolds (mm). During the second session, subjects performed a 1-RM bench press and a 1-RM leg press. Phase II of the experiment involved the development and validation of 1-RM prediction models for the bench press and the leg press exercise. Results. A stepwise regression analysis was carried out to develop a 1-RM prediction model for the bench press exercise and for the leg press exercise. The initial set of predictor variables considered for the upper body prediction model were: RTF with the bench press, body height (in.), body weight (lb), and sum of skinfolds (mm). The variable selected by the stepwise regression analysis for inclusion in the bench press prediction model was RTF with 55 lb (r = 0.914). The model to predict 1-RM bench press was: Model I: 1-RM bench press = 56.199 + 1.94(RTF55). A paired samples t-test indicated that the difference between the mean measured and mean predicted 1-RM was not significant (p>.05). The correlation between the measured and the predicted 1-RM values for the bench press was r = 0.935. The initial set of predictor variables considered for the lower body prediction model were: RTF with the leg press, body height (in.), body weight (lb), and sum of skinfolds (mm). The variables selected by the stepwise regression analysis for inclusion in the leg press prediction model were RTF with 215 lb and body weight (lb) (r = 0.798). The model to predict 1-RM leg press was: Model II: 1-RM leg press = 145.099 + 2.752 (RTF215) + .618 (body weight). A paired samples t-test indicated that the difference between the mean measured and mean predicted 1-RM was not significant (p>.05). The correlation between the measured and the predicted 1-RM values for the leg press was r = 0.695. Conclusion. The models developed in this investigation can be used to estimate the upper and/or lower body 1-RM strength of non-resistance trained women. These models will be useful for coaches, personal trainers, and fitness professionals who wish to design strength-training programs to enhance performance and the health-fitness levels of recreationally active females.