Particle bombardment method has evolved into a useful tool for biotechnologists, allowing direct gene transfer to a broad range of cells and tissues over the past several years. Some of the important applications of the process include the production of fertile transgenic crops including maize, soybean, rice, wheat, barley, sorghum, etc. Recent results have extended the range of gene transfer to animal and bacterial cells. In this article the method of particle bombardment is reviewed and discussed, and practical suggestions for improving transformation efficiency are presented.