J, H, and K broad band photometry and UV, optical, and near-IR, spectroscopy are used to investigate the star formation history of a sample of 19 starburst galaxies. By combining the reddening-corrected data, a template starburst spectrum is obtained and compared with synthetic spectra of stellar population models. At least three different stellar populations, spread over an age range of similar to 1-2x10(9) yr, are required to fit the observations. The stellar population responsible for producing the observed UV emission is characterized by constant star formation rate (SFR) and an age around 2x10(7) yr. A Salpeter Initial Mass Function (IMF) with mass range 0.1-100 M-circle dot has been used in the models, and is shown to be in agreement with the observational constraints.