Genotype imputation is a critical tool in genome-wide association studies (GWAS), allowing researchers to infer genotypes at untyped markers based on known genotypes and haplotype information. This technique enhances the power of GWAS by enabling the combination of results from studies using different genotyping platforms. The review outlines the history, theoretical foundations, and practical applications of genotype imputation, emphasizing its role in identifying genetic variants associated with complex traits. It discusses how imputation works in related and unrelated individuals, highlighting its utility in family-based studies and in large-scale population studies. The method is particularly effective in identifying rare variants and improving the accuracy of association analyses. The review also addresses the challenges of imputation in diverse populations and the importance of selecting appropriate reference panels. It highlights the increasing use of genotype imputation in the context of whole-genome resequencing, where it helps to increase the number of individuals that can be analyzed with minimal loss of accuracy. The review concludes that genotype imputation is a powerful tool that enhances the ability to detect genetic associations, especially in complex diseases, and is expected to play a key role in future genetic research.Genotype imputation is a critical tool in genome-wide association studies (GWAS), allowing researchers to infer genotypes at untyped markers based on known genotypes and haplotype information. This technique enhances the power of GWAS by enabling the combination of results from studies using different genotyping platforms. The review outlines the history, theoretical foundations, and practical applications of genotype imputation, emphasizing its role in identifying genetic variants associated with complex traits. It discusses how imputation works in related and unrelated individuals, highlighting its utility in family-based studies and in large-scale population studies. The method is particularly effective in identifying rare variants and improving the accuracy of association analyses. The review also addresses the challenges of imputation in diverse populations and the importance of selecting appropriate reference panels. It highlights the increasing use of genotype imputation in the context of whole-genome resequencing, where it helps to increase the number of individuals that can be analyzed with minimal loss of accuracy. The review concludes that genotype imputation is a powerful tool that enhances the ability to detect genetic associations, especially in complex diseases, and is expected to play a key role in future genetic research.