The Dictyostelium actin genes constitute a seventeen-member dispersed multigene family. At least nine of the seventeen genes are expressed. Nearly all of the genes seem to code for the same protein sequence, although one gene with a variant amino acid sequence is expressed. The 5' untranslated and untranscribed sequences as well as the 3' untranscribed sequences are not conserved from gene to gene, although TATA and poly(T) sequences are found in the region of transcription initiation. The 3' untranslated sequences are conserved within some groups of genes. This allows us to suggest an evolutionary history of the actin gene duplications. We have developed a DNA mediated transformation system for Dictyostelium. We will soon be able to use this system to examine the importance of various regions around the actin genes for proper control of gene expression and to identify sequences involved in developmental regulation.