Toshiatsu's children were Toshiyuki DOI (second son), Toshihiro (third son), a daughter (lawful wife of Tateyuki HOSOKAWA), and a daughter (wife of Naonori NAGAI).
子に土井利之（次男）、土井利広（三男）、娘（細川立之正室）、娘（永井直興室）。