The mitogen activated protein kinase (MAPK) cascade is a central signal transduction platform, ubiquitous within the eukaryotes. MAPKs function prominently in different essential cellular processes such as proliferation, differentiation, survival and defense to pathogen attack. The 32 MAPKs of Glycine max (soybean) have been examined functionally to determine if they have any defense role, focusing in on infection by the plant-parasitic nematode Heterodera glycines. Of these 32 MAPKs, 9 have been shown to have a defense function. The Mitogen Activated Protein Kinase database (MAPKDB) has been developed to assist the research community in this regard. The MAPKDB allows users to search the annotations and sequencing data of G. max transgenic lines undergoing overexpression (OE) or RNA interference (RNAi) of its defense map kinases. These defense MAPKs include map kinase 2 (MPK2), MPK3, MPK4, MPK5, MPK6, MPK13, MPK16, and MPK20. The database also contains data analysis information for each sample that helps to detect the differential expression of the genes identified within these samples. The database has been developed using SQL Server 2016 to manage G. max MAPK sequences and the sequence alignment of 18 different samples with two additional OE and RNAi control experiments for a total of 20 samples. The MAPKDB web application can be accessed publicly via a web-based browser, affording a friendly method for scientists and users to browse and search sequences and gene expression data that are stored in the MAPKDB database.