We have developed computer program (DBSEQ) to construct nucleic acid sequence database and protein sequence database on 16-blt personal computer system. The source of nucleotide sequence data is the genetie sequence data bank GenBank Rrelease 48.0 floppy disk version. DBSEQ system consists of one main menu program and 9 executing programs. Five of them are retrieval programs for different kinds of keywords, such as protein names, oranism names, author names , human gene symbols and accession unmbers. Other four executing programs are developed for sequence data access, codon transiation , with different modes and sequence data display.Human histone 4 gene is used to show these functions of DBSEQ system.