We developed a web-based Y chromosomal short tandem repeat (Y-STR) database (ySTRmanager, http://ystrmanager.yonsei.ac.kr) to facilitate calculation of Y-STR haplotype frequency estimates for random matches and kinship indices for various relationship levels. The ySTRmanager database provides 3 functions: (i) Y-STR haplotype search, (ii) kinship index calculation, and (iii) user database configuration. The Y-STR haplotype search function allows researchers to retrieve Y-STR haplotypes that meet queried Y-STR allele, Y-haplogroup affiliation, and/or sample information from a selected population in the open database, which consists of 12-17 Y-STR loci. The number of matches in a selected population, haplotype frequency estimator, and detailed results for matched and neighbor haplotypes are displayed as a set of search results. The kinship index calculation function provides kinship indices of 2 input Y-STR haplotypes for the relationship represented by the number of meioses, with consideration of target population and mutation rate of each Y-STR. In addition, ySTRmanager allows registered users to configure their own database to store and analyze Y-STR haplotype and/or mutation rate data. The stored Y-STR data can be used in the search function and in the analysis to obtain forensic statistical values. The ySTRmanager will be a useful system to analyze and manage Y-STR data in the practice of forensic genetics.