Intestinal parasitic infections has had remarked impact on public heath, particularly among peoples living under standard levels of sanitation and poor hygienic conditions (Alfellani et al., 2013). Blastocystis hominis is the most common intestinal parasite in humans and many other animals (Windsor et al., 2002). Blastocystis, an unusual anaerobic, single-celled stramenopile, is a remarkably successful intestinal parasite of a vast array of host species including humans (Stensvold, 2013). Infections with this organism are spread worldwide and it is often the most frequently isolated protozoan in parasitological surveys (Boorom et al., 2008; Chandramathi et al., 2010; Roldan et al., 2009). In developing countries, B. hominis has higher prevalence (30 to 50%) in comparison with developed countries (1.5 to 10%)(Li et al., 2007). The pathogenicity of B. hominis still has been debated. A report supporting the pathogenic potential of this parasite (Ok et al., 1999); that can be found in patients with or without gastrointestinal symptoms. Some of the symptoms associated with Blastocystis infection include abdominal pain, constipation, diarrhea, alternating diarrhea and constipation and others (Qadri et al., 1989). Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder of unknown cause with the same above symptoms (Wilson et al., 2004). Inflammatory bowel disease (IBD) is a disease of unknown cause associated with diarrhea and colonic lesions that are identified by endoscopy (Sands 2006). However other studies state an opponent view point and it is believed that other factors probably are the causing agents of these symptoms (Kaya et al., 2007; Hussein et al., 2008). Morphologically the parasite has four phases: vacuolar, granular, amoebic and cystic phase. The later phase has been considered a dominant phase found in environment (soil and water) so, it acts as vehicle for transmitting the parasite into the host. Human to human and human to animal transmission was not obvious (Yoshikawa et al., 2004). Diagnosis of B. hominis overlap with other causatives of diarrhea specially the size of the cysts that measures 3 to 10 μm which is close to oocysist of Cyclospora, Entamoeba histolytica and other protozoan parasites (Tan, 2004). Routinely direct microscopy by preparing of wet preparation of Lugol's iodine, fecal smear staining with trichrome stain can demonstrate B. hominis (Tan, 2008), but Blastocystis poses considerable challenges for the diagnostic laboratory. Firstly, the uncertain pathogenesis of the parasite discourages many clinicians from considering Blastocystis to be the etiological agent of disease. Secondly, the polymorphic nature of the organism in wet mounts can result in confusion with yeast, Cyclospora sp., or fat globules (Stenzel et al., 1994). For these reasons alternative methods such as serology particularly ELISA using copro-antigen kit was invited to detect B. hominis in stool samples rather than direct microscopy (Stenzel et al., 1997). Information about B. hominis in Iraq was not clear, except the study was carried out in south part of Baghdad by Raof and Abdul-Raham (2011) and in Kirkuk karyaghdi (2013) when they carried out diagnostic study on some intestinal parasites, via which B. hominis contributed 3.6%. In 2015, Salman in Kirkuk city/Iraq who carried on a comparative study using direct microscopy and ELISA-copro antigen test for detecting Blastocystis hominis rate among peoples with irritable bowel syndrome, he found the all rate of Blastocystosis 58.22% This rate was contributed 59.44% and 58.99% for direct microscopy finding and ELISA testing. Statistically the differences between