We review the most classical questions addressed by the analysis of population data in immunogenetics. Basic genetics' definitions are reminded. Questions related to the population data itself (structure, missing values nomenclature, sampling) are developed first, and secondly, the population genetics questions (relevance of genetic parameters (phenotype, genotype allele and haplotype frequencies; genetic distances; linkage disequilibrium measures), methods and practical computing) are illustrated by immunogenetics polymorphisms. This article gives the essential of population immunogenetics on examples and key references. We underline the importance of population dimension in statistical analysis structure of linkage disequilibrium and genetic diversity between populations may affect the power of the study or the interpretation of correlations between markers, genes and diseases, making population genetics both theoretical and very practical.