Giardia lamblia is one of the most prevalent intestinal protozoa in the world, which affect children in both undeveloped and developing countries. This study aimed to determine genotypes of the Giardia lamblia using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP)-PCR techniques. Additionally, the relationship between genotype patterns and their geographical distribution, gender, and age was investigated. Methods: The current study included 926 samples of

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... s of children suffering from diarrhoea, who visits the internal clinics at Teaching Hospital, and Child Hospital in AL- Diwaniyah City from November 2012 - Jun 2013. For age groups of 1-12 years exclusively. The samples were examined using a direct mount wet smear, The positive samples were preserved without adding preservatives at a temperature of -20°C until the DNA extraction for G. lamblia genotyping by using PCR and RFLP-PCR technique. Results: Giardia lamblia was detected in 2.15% (20/926) of samples from diarrhea cases in children by amplification of glutamate dehydrogenase gene (gdh) using two specific primers GDHiR and GDHiF. It was revealed that 7 samples belonged to genotype A (35%) and 13 samples belonged to genotype B (65%). All genotype A samples belonged to subgenotype AII (100%), while genotype B samples belonged to subgenotypes BIII (53.61 %) and BIV (47.38 %). Genotype A was detected in children of 1-6 years of age while B genotype was detected in all age groups. Both of the genotypes have been detected in both genders (male and female) and genotype B was found in both urban and rural areas; however, its prevalence was higher in rural areas than in urban areas (100% and 30%, respectively). Conclusion: There are two genotypes of Giardia lamblia, genotype A and genotype B, each of which has secondary genetic patterns which include AII, BIII, and BIV.