In this paper, we use case-parent triad families as the data structure to demonstrate how to proceed sequential linkage analysis. We adopt two types of linkage methods, the unified-parameter likelihood method and the transmission/disequilibrium test (TDT) method, to implement this sequential test procedure. Under different genetic scenarios, our simulation studies show that the unified-parameter sequential likelihood method requires less sample sizes to reach the sequential decision boundary than the TDT sequential method.