An attempt was made to investigate and analyze certain factors which, it was presumed, were responsible for the high irrigation costs in agricultural development of the farms in the Lajas Valley. The factors included were: water available for irrigation; topography of the farms; types of soil; irrigation methods employed; administrative aspects of the system; structural amenities of the farms; maintenance of irrigation and drainage structures; size of the agricultural unit; land use and handling of water in the farms. The study showed that among the factors investigated, the following are those which exercise the most significant influence on the costs of irrigation operations: topography of the farms; the administrative aspects of the system; methods of irrigation employed, and the size of the agricultural unit. (Author)