A matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer has been constructed at the Department of Physics, University of Colombo, Sri Lanka. In this mass spectrometer, a solid sample which contains analyte molecules embedded in a suitable matrix compound in excess is exposed to a UV pulsed nitrogen laser source (λ = 337 nm). The desorbed secondary ions from the sample are mass analyzed using the time-of-flight technique. The first MALDI-TOF mass spectra of two peptides namely [tyr 8 ]-bradykinin (1076.2 u) and porcine N-acetyl renin substrate tetradecapeptide (1801.1 u) with the matrix 2,5 di-hydro benzoic acid (154.1 u) have been obtained. Each peptide produced a MH + peak corresponding to its intact molecular ion with m/q values of 1089 ± 6 and 1794 ± 8 respectively.