Significant cost overruns and schedule delays on oil and gas projects in Alberta have been of great concern for many companies. The industry has indicated a need for public data to verify anecdotal conclusions that labor productivity is the root cause behind project performance problems. In this paper, a sample of 37 Alberta oil and gas projects was analyzed. The findings provided evidence that poor planning and inadequate project scope definition gave rise to project cost and schedule performance problems, while labor productivity is merely a proximate cause. High correlations are revealed between deficient project performance and factors such as low percent engineering completed before construction start, low estimation accuracy of field productivity rates, unit costs, crew sizes, and indirect costs. The results also emphasized a need to increase the level of implementation of best management practices to ameliorate the effects of the challenging project environments.