In this paper, we examine the causal relationship between diesel consumption, CO2 emissions and GDP in Cameroon during the period 1975-2008. Cointegration and vector error-correction modelling techniques are used in this study. ADF tests show that the series, after logarithmic transformation, are non-stationary and integrated of order one.This study finds the presence of a long-run equilibrium relationship between the variables. The results of the Granger-causality tests for time series have been estimated.