The distribution of a homologous series of p-alkylpyridines between water and six organic solvents with varying degrees of polarity was investigated. The distribution coefficients were considered as reflections of the strength of net interactions involved in the solvents. The order was chloroform greater than octanol greater than carbon tetrachloride greater than butyl ether greater than hexadecane greater than octane. The effect of the methylene group upon the distribution coefficients differed little among the six solvents. The relative constancy was attributed to the predominance of the dispersion forces in the incremental effect.