Variation order is regarded as the most occurrence issue and often resulted to conflicts, delay and disputes among the parties to contracts. The study sought the perceptions of professionals on the significant factors causing variation order and their attached impacts. A preliminary survey were carried out on the identified causes in the literature and the respondents asked to ticks the most common occurrence ones within the study area, these make the basis of questionnaire used. A total of one hundred questionnaires administered to various respondents and sixty two retrieved. A mean scored was adopted and used in analyzing the data. The study reported that, change in specification (MS= 23.28), change in design (MS= 19.98), defectives workmanship (MS= 17.46) and change in government regulation (MS= 19.44) are the most significant factors causing variation order in the study area. It conclude that, consultant and client related changes with (MS= 117.90 and 115.62) are the main origin of variation order and recommend that, prior to design stage, the consultants’ should ascertained the full details requirement of client on design and specification issues and also the client should employ only the competent and experience consultant to execute the works.