The purpose of this study was to examine the integration between upstream and downstream supply chain of oil and gas products and determine its effect on improving efficiency.The study was conducted in City Council of Dodoma (CCD) and it adopted a cross-sectional survey design involving a sample size of 80 staff working at oil and gas service stations. The study employed simple random sampling technique to get respondents. Structured questionnaires scaled to 5-point Likert scale were used to capture data from the respondents. Data were analyzed by using Multiple Regression Model to determine whether the four independent variables have significant contribution on improving efficiency in supply chain management. The results indicate that three variables out of four (i.e. information, transport and legal systems) have a significant contribution on efficiency (p=0.000; p=0.000 and p=0.028 respectively). The study concluded that effective integration of information, transport and legal systems between upstream and downstream partners is essential for improving efficiency in oil and gas supply chain. The paper recommends that upstream and downstream supply chain partners should effectively integrate their systems to improve efficiency in supplying of oil and gas products in Tanzania.