One of the more appropriate choices for having a competitive and market oriented agriculture sector as well as being more active in the world market is to develop greenhouse enterprises. Climate diversification, availability of manpower, technical knowledge and cheap energy are some encouraging reasons for development of greenhouses in Iran. The purpose of this research was an analysis of the promoter factors affecting the horticultural greenhouse units, development. A survey method of research was employed, the statistical population being consisted of the greenhouse owners in Varamin. A Snow-ball (n=90) was employed. The instrument of research was a questionnaire, developed as based on the background available on the subject. Cronbach’s alpha coefficient was calculated as equal to 0.82 indicating the reliability of the questionnaire. Also, content and face validity of the questionnaire was confirmed as based on experts’ opinions. Analysis of data was done making use of SPSS software. Findings indicated that economy, technique, individuals and vocations, infrastructure, and support of the government are among the determining factors in development of horticulture greenhouse units. These could explain 83.07% of the variation in the development of horticultural greenhouse units.