Nuclear magnetic resonance (NMR) imaging and spectroscopy were used to assess body composition of the chicken and turkey poult. The NMR imaging was performed using a clinical, whole-body imaging system operating at 1.5 tesla (T; 63 MHz). Three-dimensional reconstruction of cross-sectional images made along the transaxial plane was used to estimate mass of the Pectoralis muscle of chickens ranging in weight from 140 to 2,760 g. Results indicate that NMR imaging can be used to determine size of the Pectoralis muscle (R2 = .99) in the bird, thus permitting repetitive measurements during the growth and development of the bird. The NMR spectroscopy was performed using an imaging spectrometer operating at 4.7 T (200 MHz). Integral areas of the water and lipid proton peaks of the spectra were compared with the water and lipid content of the whole body as determined by chemical analysis. Regression analysis of measurements made on turkey poults, ranging in weight from 115 to 630 g (n = 6), resulted in R2 values of .94 for NMR water proton peak area and total body water, .93 for NMR lipid proton peak area and total body lipid, and .96 for NMR water proton peak area and total body protein. From NMR spectroscopy of chickens weighing 528 +/- 18 g (n = 6), the relative area of the lipid peak correlated with whole-body lipid (R2 = .97). Thus, whole-body spectroscopy of smaller birds can be used to measure total body water, protein, and lipid content.