[en] This paper introduces the present status of the JAERI Material Performance Database (JMPD) and examples of its utilization. In JAERI, the JMPD has been developed since 1986 with a view to utilizing various kinds of characteristic data of nuclear materials efficiently. Management system of relational database, PLANNER, was employed and supporting systems for data retrieval and output were expanded. In order to improve user-friendliness of the retrieval system, the menu selection type procedures have been developed where knowledge of the system or the data structures are not required for end-users. The retrieved data can also be processed readily through supporting systems for graphical and statistical analyses. As to utilization of the JMPD, two types of data analyses are mentioned as follows: (1) A series of statistical analyses was performed in order to estimate design values both of the yield strength (Sy) and of the tensile strength (Su) for aluminum alloys which are widely used as structural materials of research reactors. (2) Statistical analyses were accomplished by using the cyclic crack growth rate data for nuclear pressure vessel steels stored in the JMPD, and comparisons were made on variability and/or reproducibility of the data between obtained by ΔK-increasing and ΔK-constant type tests. (author)