Cross sectional study was conducted from November, 2010 to March 2011 to assess the Constraints associated with artificial insemination service in four purposively selected districts of Wolaita Zone. A questionnaire survey was conducted on 384 randomly selected household heads. Moreover, five AITs and two liquid nitrogen production center experts were purposely included in the study. According to the study, the major constraints of artificial insemination revealed by farmers were lack of regular and consistent AI service 379 (98.7%), lack of mobile AI service 363 (94.5%), lack of weekend AI service 357 (93%), shortage of AITs 352 (91.7%), shortage of inputs 273 (71.1%), absence of private AI service 384 (100%), lack of awareness training about AI 353 (91.9%), occurrence of dystocia due to incompatibility of cow�s pelvic cavity with calf size 66 (17.2%). The study also showed inappropriate timing of insemination by farmers, i.e. early insemination 187 (48.7%) and late insemination 128 (33.3%) as a constraint to AI failure. There was a statistically significant difference among the districts (p< 0.05) at 95% confidence interval with respect to the risk factors that included mobile AI service availability, weekends AI service availability, input availability, availability of awareness training, timing of insemination, and occurrence of dystocia associated with AI service. The major constraints of artificial insemination service revealed by AITs were lack of awareness 4 (80%), inappropriate timing of insemination by farmers 5 (100%), shortage of inputs 3 (60%), lack of mobile AI service 4 (80%), lack of incentives and on-the-job trainings to AITs 5 (100%), lack of appropriate cooperation among responsible bodies 5 (100%). Evaluation of technical skill of AITs revealed that one (20%) of them was technically excellent, two (40%) were good, and the remaining two (40%) were poor. There was no statistically significant difference among the districts with respect to all the risk factors used to assess constraints of AI service mentioned by AITs (p>0.05). The constraints mentioned by liquid nitrogen production center experts were low production capacity of the center due to poor technical performance of the facility and little attention from the regional bureau of agriculture. The retrospective data revealed that areal coverage of AI service is 7-10 km radius from AI centers which is quite below the demand. It is concluded that the efficiency of AI service in the area is hindered by different constraints. Therefore, responsible bodies must exert their utmost effort to overcome the constraints and ensure reliable and efficient AI service.