Recent surveys investigating the molecular biology of Giardia lamblia revealed two distinct assemblages with different clinical outcomes. However, there is not a universal compromise about the clinical effects of each assemblage, warranting further studies. Here, we report the results of the first analyses of the assemblages of G. lamblia in Manisa province located in western Turkey, together with their relationships with the symptoms and DNA sequence analyses of the PCR products. DNA samples were isolated from the stools of 63 patients infected with G. lamblia and 54 DNA samples, amplified successfully with PCR, were digested with the enzyme Xho I for RFLP. Thirty-eight of 54 samples (70.4%) were found to be in Assemblage A, while the remaining 16 samples (29.6%) were found to be in Assemblage B. The number of female patients was found significantly higher in Assemblage B (P=0.18). There was a statistically significant relationship between the occurrence of both abdominal pain and diarrhea and Assemblage B (chi-square, 10.52; P<0.05). No other statistically significant relationship was detected between the assemblages and neither with the symptoms nor with the age groups of the patients. The comparison of the DNA sequences of the PCR products from two assemblage B (one subtype B1 and one B) and one assemblage A samples both with each other and with other DNA sequences in the NCBI website by multialignment analyses, revealed specific regions for assemblages B (B1-B) and A on tpi gene region. Further studies with more patients are required to assess these initial results. Now, our aim is to design a probe for tpi gene region to set up a real-time PCR assay that is easier to conduct and requiring shorter time for the analyses.