The study was conducted to evaluate the constraints of AI delivery systems and service efficiency and reproductive performance of crossbred and local cows in central highlands of Ethiopia The assessment of survey result was based on diagnostic survey of 132 sample households, focus group discussions, on-farm experiments aimed at evaluating factors affecting efficiency of AI at on-farm conditions & effect of supplementation on occurrence of estrus and subsequent conception rate. The livestock herd was dominated by sheep and cattle comprising the overall mean of 46.5 and 19.3 of the total stock in the study area, respectively. The survey indicated that the major constraints for AI delivery and service efficiency as ranked by the proportions of respondents from all locations were; shortage of AI technician (79.99%), shortage of inputs (76.72%), requirement for repeated services (18.17%), communication problems (24.81%), season of insemination (52.14) and parity of cows (48.19). The retrospective study was conducted on 682 crossbred & local cows to assess efficiency of reproductive performance associated with AI service. The first service NRR in the retrospective study was 69.67%. The overall mean ISI and CFIS in the retrospective study were 33.1 and 255.9 days, respectively. Similarly, the overall mean value ofNSC was 1.9 and Cl was 568.50 days from the result of retrospective data analysis. The analysis of variance indicated that breed, parity, management systems and AITs had exerted significant (p < 0.0001) effect on ISI, whereas year of calving and season of calving had not significant (p > 0.05) effect on ISI Of all genetic and non-genetic sources of variations tested by the least squares analysis of variance breed, parity, management systems, season of calving and year of calving had significant (p < 0.05) effect on NSC, whereas AITs had no significant (p > 0.05) association with NSC. Similarly, the result of this study showed that breed, parity, management and AITs (p < 0.05) influenced on CFIS, whereas season of calving and year of calving had no significant (p > 0.05) effect on CFIS. Moreover, breed of cows, parity, management and AITs had imparted significant (p < 0.05) effect on Cl, whereas year of calving and season of calving refuted significant (p > 0.05) effect on CIOn the other hand, the result of this study confirmed that efficiency of AI system in terms of calf crop was estimated to be around 35.12%, while efficiency of the AI system in terms cost disclosed that a single calf from AI demanded an expenditure of about 520 ETB. Generally, it can be inferred that artificial insemination operation in the study area is not a successful tool and requires urgent measures to rectify major challenges as beneficiaries may totally decline using it.