Abstract Due to the challenges associated with breast cancer prognosis, this study examined sialic acid levels based on subtypes, grades and therapeutic courses among breast cancer patients presenting at Ahmadu Bello University Teaching Hospital (ABUTH) in North-Western Nigeria between June 2019 and December 2020. This was a cross-sectional study. Sociodemographic characteristics, total sialic acid (TSA), free sialic acid (FSA), bound sialic acid (BSA) and haematological parameters were determined. The mean age of the respondents was 47.46 ± 10.71 years, and the modal age range was 41-50 years. About 40% of the patients had triple-negative breast cancer subtype, and 83.1% had invasive carcinoma. There was an association between breast cancer grade and body mass index (χ2= 26.306, P= 0.001). The TSA, FSA and BSA concentrations were significantly (P<0.05) higher in luminal A and triple-negative breast cancer patients when compared to apparently healthy controls and were highest in stage IV patients. The TSA correlated with the third and sixth chemotherapy courses. Significant (P<0.05) decrease was observed in PCV and Hb among the breast cancer patients irrespective of subtype compared to healthy control. The results suggest that TSA, FSA and BSA were higher in breast cancer patients, necessitating further research on their possible prognostic implications.