Growth factors (GFs) are naturally occurring proteins or steroid hormones which act as signaling molecules between cells that play a key role in the processes of proliferation, cell differentiation and maturation of a wide variety of cells and tissues. A recently purified synthetic basic b-FGF was assessed using a routine tissue culture assay via application of a wide range of doses ranged between 0.1 and 300 ng/mL of the basic fibroblast growth factor (b-FGF) in phosphate buffer saline (PBS) and 10% fetal calf serum (FCS) on the growth rate of Rama-27 mammary cell line. Applying SPSS "Student T-test" biostatistics the result showed significant increase (p ≤ 0.05), almost 7 folds in tissue proliferation at a low dose of 0.3 ng/mL FGF in comparison with control tissue (PBS) only. It is concluded that 0.3 ng/mL dose represents the lower optimal dose suggesting its possibility of an in vivo technique to test its potency in curing skin wounds in rats.