As knowledge of the human genome continues to grow, more progress is being made towards not only identifying the genes involved in disease susceptibility but also in defining the synergistic role genes play with environmental exposures. The detection of gene-environment interactions is important as it can offer clinicians a potential means of intervention. The discovery of interactions relies heavily on powerful statistical methods. We present a test, FBAT-I, that can be used to investigate gene-environment interaction. The test uses the case-parent triad design and protects the statistical inference from potential spurious results due to population admixture.