Abstract. Full text article available at https://www.ajol.info/index.php/thrb/article/view/151951Despite scaling up of HIV and treatment services to improve the outcome of people living with HIV, still a high proportion of patients seek out medical attention at late stages of the disease. This contributes to late initiation of ART and poor clinical outcome especially in sub Saharan Africa. The literature on magnitude of this problem in Tanzania is still scarce. This study aimed to determine the prevalence and associated factors of delayed HIV diagnosis in rural Tanzania. This was a cross sectional study, involving newly diagnosed adult HIV patients sent in for care and treatment linkage. Information regarding age, sex, WHO stage, type of opportunistic condition, HIV testing service and on diagnosis CD4 counts were all collected. On diagnosis CD4 counts <200cells/µl was coded as Late HIV diagnosis. The proportion of with Late HIV diagnosis was calculated and logistic regression modal was used to determine the degree of association of different variables at 95%CI. In total 649 patients were included in this study. The median age of the study participants was 45.5 years most of them being females 396 (61.02%). The median CD4 count was 168 cells/µl and majority of our study participants 468 (72.11%) were in WHO clinical stage 3&4. Overall 385 (59.32%) were found to have Late HIV diagnosis where 303 (78.70%) had stage 3&4 AIDS defining illness (OR=2.2, p<0.001). Male patients were predominantly affected (OR=1.4, p=0.035), who were more likely to be tested following PITC service (OR=30, p<0.001). Late HIV diagnosis is prevalent in our setting with high prevalence of most of the stage 3&4 AIDS defining illnesses. Male patients are predominantly affected as late presenters. There is a need to strengthen and extend the available Provider Initiated Testing and Counselling activities to primary health care level.