Myotonic dystrophy (DM) is a multisystemic neuromuscular disorder caused by a dynamic mutation of (CTG) trinucleotide repeats in the 3 untranslated region of the myotonic dystrophy protein kinase gene (DMPK). The aim of the present study was to establish the use of polymerase chain reaction (PCR)-based simple and rapid method for initial sample screening. Only a minority of samples were tested positive with the above method and need to be detected by tri primer (TP)-PCR and southern blotting which is more time consuming and involves use of radioactive material. This study concerned 24 patients from nine families with a clinical diagnosis of the DM1. DNA extracted from the blood was used for amplification of the triplet repeat sequences at the DMPK loci. We obtained two bands for the normal subjects and one band for patients corresponding to normal DMPK allele, confirmed by the TP-PCR and the southern blot. This rapid test for initial screening of samples for the presence of DMPK mutations is economical and reliable method. This method reduces the number of samples needing TP-PCR and southern blotting.