Infertility is a common gynaecological problem which remains unexplained in 10-30% cases. This study explores the difference of blood levels of homocysteine between women with unexplained infertility and normal fertility. This was a cross-sectional study conducted from January 2015 to December 2015 in the Department of Gynaecology and Obstetrics of a tertiary care hospital of Bangladesh drawing 30 women with normal fertility as controls and 30 with unexplained infertility as cases. The subjects in both groups were well matched in terms of age (p value 0.875) as well as height, weight and BMI (p value 0.418). There was no statistically significant difference between the two groups in socio-economic status and educational levels. The two groups had similar duration of marriage (7.88±3.5 years in controls vs. 8.15±3.88 years in cases) and coital frequency (3.63±0.76 week in controls vs. 3.33±0.55 week in cases). Based on the institutional cut-off value for normal serum fasting homocysteine level of 15 micromoles/L, the frequency of hyper-homocysteinemia was significantly higher (40%) in unexplained infertility group compared to control group (16.7%, p value 0.044). Fasting serum homocysteine levels were significantly higher in the unexplained infertility group compared to the normal fertility group (13.46±5.05 vs. 9.87±4.84 micromoles/L, p value 0.007). Serum fasting homocysteine levels and frequency of hyper-homocysteinemia were increased in women with unexplained infertility compared to age and BMI matched women with normal fertility.