Breast carcinoma is one the three leading cancers afflicting women in Uganda. Its incidence has doubled since the 1960s. It has a markedly diverse clinical and biological behaviour.Unlike their white counterparts,the majority of black African patients are in their reproductive age bracket and they present with advanced systemic disease when only palliation is the remaining treatment option. Knowledge of the ER status is vital for the planning of treatment of these patients especially when hormonal therapy is anticipated. This was the first documented IHA based study on the ER status of black African women with primary breast carcinoma. it was a cross sectional study on 66 patients. Also studied was the relationship between ER status and socio-demographic, clinical and laboratory(tumour histological grade)variables.The prevalence of ER positivity was 62.1% and there was no significant relationship between ER status and those variables. The study showed that ER status of the patients could not be deduced from any of these variables.It is an individual characteristic that can only be established by ER assay.