Small ruminant industry is threatened in tropical and sub-tropical countries due to a Theileria (T.) lestoquardi, a haemoprotozoan. A Loop-Mediated Isothermal Amplification (LAMP) assay was developed for diagnosis of T. lestoquardi, a major cause of ovine theileriosis. The primers were designed based on the clone-5 sequence of T. lestoquardi. Four types of geo-climatic regions were selected for sampling. Towards this end, 56% sheep were infected with T. lestoquardi in the study area. 9.1% were found infected by using Giemsa staining technique, whereas, 13 and 17.1% by polymerase chain reaction (PCR) and loop mediated isothermal amplification (LAMP), respectively. PCR was considered a reference test to evaluate specificity and sensitivity of LAMP. The relative specificity and sensitivity of LAMP assay was 94.4 and 78%, respectively. Findings of LAMP assay revealed that the highest prevalence was detected in Bahawalpur (21.6% 19/88*100) followed in order by Jhang (17.04% 15/88*100), Sahiwal (15.09% 14/88*100) and Faisalabad (13.63% 12/88*100). LAMP assay found most suitable test for diagnosis of T. lestoquardi. This is anticipated that this study will provide a base-line data for caretakers and veterinary personnel to devise an improved scheme for the effective control of ovine theileriosis. [ABSTRACT FROM AUTHOR]