Rationale and Objectives. The clinical feasibility and application of the maximum entropy method for data analysis from in vivo phosphorus-31-magnetic resonance (P-31-MR) spectra of the liver were determined. Methods. Image-guided localized P-31-MR spectroscopy was performed in 24 patients with liver metastascs and in 20 healthy volunteers. The spectra were obtained with a whole body scanner operating at 1.5 T using a surface coil. Phospho-monoester/β-adenosine triphosphate (ATP), phosphodiestcr /β-ATP, and inorganic phosphate/β-ATP were calculated from the maximum entropy method-spectra and from spectra evaluated with standard data processing (Fourier transformation spectra). Results. Phosphomonoestcr/β-ATP and phosphodiester /β-ATP were increased significantly with both methods in patients' spectra. Maximum entropy method spectra showed a distinct pattern with low noise. It was easier to determine peak borders and to attach resonances to the different metabolites using this method. Conclusions. Maximum entropy method is an alternative method for evaluation and quantification of P-31-MR spectra data and is preferred to standard data processing with Fourier transformation in eases of reduced signal-to-noise ratio of spectra.