Sibship methods have been shown to be more powerful than traditional sib‐pair methods in mapping quantative trait loci. We propose a statistical procedure which integrates data on sibships into a so‐called ‘contrast function’, a natural extension of the classical squared sib‐pair trait difference proposed by Haseman & Elston (1972). We also develop a combined mean and contrast function which provides more information on linkage compared to the contrast function. Our method is extended to multiple, epistatically interacting trait loci. Monte‐Carlo simulations are included to compare the efficiencies of the proposed procedures with some currently used methods. An application of our proposed method is presented using data on alcohol dependence.