This paper investigates the effects of different factors on development of open source enterprise resources planning software packages. The study designs a questionnaire in Likert scale and distributes it among 210 experts in the field of open source software package development. Cronbach alpha has been calculated as 0.93, which is well above the minimum acceptable level. Using Pearson correlation as well as stepwise regression analysis, the study determines three most important factors including fundamental issues, during and after implementation of open source software development. The study also determines a positive and strong relationship between fundamental factors and after implementation factors (r=0.9006, Sig. = 0.000).