Background: Ankylosing spondylitis (AS) is a chronic inflammatory disease mainly affecting the spine and sacroiliac joints. Macrophage migration inhibitory (MIF) factor is a regulatory cytokine that inhibits random immune cell migration. MIF gene promoter polymorphisms play a role in the progression of several inflammatory disorders. Aims: To investigate the relationship between the MIF gene -173 G/C single-nucleotide polymorphism (SNP) and AS. Study Design: Cross-sectional study. Methods: In this study, a total of 161 AS and 194 normal controls were recruited. The MIF gene -173 G/C SNP was analyzed by polymerase chain reaction using the restriction fragment length polymorphism method. Results: There was no significant difference between groups in terms of genotype distribution (p>0.05). When wild-type G/G and G/C+ C/C genotypes are compared in terms of clinical characteristics, there is a significant difference between the average age and the duration of disease in AS patients (p<0.05). Conclusion: No significant relationship between AS disease and MIF -173 G/C polymorphism was found. MIF -173 G/C polymorphism (C allele) may affect the time of onset and the duration of disease in AS patients.