An IR ATR spectroscopic method combined with Partial Least Squares (PLS) regression was developed for the simultaneous quantitative analysis of total protein, lipid and fatty acids in algae biomass. The developed multiple-species model could be used to screen a large number of algae. The method allows making fast choice of the algae species rich in proteins, lipids or carbohydrates dependent on the aim of the further processing of the biomass and isolation of specific biochemicals. Large differences in biomass composition were observed between the various algae species. Protein content as determined by ATR spectroscopy correlated well with the results obtained from elemental analysis and the lipid and fatty acids content correlated well with the results of gravimetric and GC-MS methods accordingly. The ATR method facilitates and speeds up selection for biomolecules of nutritional interest, such as proteins, lipids, carbohydrates and fatty acids.