This study analyzes the correlation and the interaction among commodity groups which determine the inflation rate in West Sumatera. Using the monthly data from January 2002 to December 2008 the estimation applies the Vector Error Correction Model (VECM) in order to analyze the dynamics of commodity prices in the model. The results show some groups have significant contributions in determining other group prices. We found that the volality of Prepared Food Drink Cigarette and Tobacco is affected by Food group Transportation Communication and Financial Services. All commodity group is mostly affected by its own movement especially for the high regulated prices group Water Electricity and Fuel group including Housing. This paper underlines that in controlling regional inflation the partial effort by focusing only on the basket goods which gives the highest contribution to the regional inflation (i.e. foodstuff and prepared food) is not effective when the region faces high volatility in other basket goods (i.e. transportation). The price determining of basket goods is a simultaneous process and controlling the regional inflation needs greater concern to all goods. The government intervention on the price setting is also one of the important parts in causing the volatility of the basket goods.