The present study is designed to diagnose the giardiasis from cattle and patients with diarrhea arrivals to Maternity and Childhood Teaching Hospital and General Education Hospital in Al-Qadisiya Governorate by using direct wet smear method as well as knowledge of the rate of prevalence of giardiasis in Al- Diwaniyah province, and study the effect of age, sex and nature of residence in the proportions of infection and investigate the genotypes of Giardia lamblia from human and animal feces ,100 samples were collected (50 stool samples of human and 50 feces samples of cattle). In human, the result showed that the infection rate was 54% (27). The age group of 2-4 years showed the highest rate of infection (40.7%), while children aged 8-10 years showed the lowest rate of infection (3.7%). The results showed that 16 (59.2%) out of 27 and 11 (47.8%) out of 23 of males and females were positive respectively, so the rate of females cases were higher than males , with non-significant differences at p > 0.05 . It was found that the majority of cases (66.6%) were from rural areas. DNA was extracted from positive samples (25 samples of human and 25 samples of cattle ) then after amplified using primers for triosephosphateisomerase (tpi) gene that specific for genotyping A and B, the result showed that 17(68%) were genotype B and 3(12%) were genotype A, while 5(20%) were both genotype A and B. However in cattle, the result showed that the infection rate was 70% (35). The age group of <6 month showed the highest rate of infection was (45.7%), while calves aged 6month-1year showed the lowest rate of infection was (22.8%). The results showed the number of positive cases according to the sex were 14 (40%) and 21(60%) in male and female respectively that showed higher positively of females when compared with males with significant difference at p<0.05. The result of distribution of genotypes of Giardia lamblia in cattle showed that 16(64%) were genotype B and 5(20%) were genotype A while 4(16%) were both genotype A and B.