This study concerns a new photometer head assembly which has been designed especially for use in visible microphotometry. This assembly consists of three principal units: (1) a Farrand type B photocell mount; (2) a viewing unit modified from the prism housing and side tube of a Leitz Micro-Ibso attachment; and (3) a base plate taken from a Leitz sliding photometer mount. Aside from providing optimum stability and operational convenience, this head assembly meets all of the essential optical requirements necessary for microphotometric work in the visible spectrum. Also, the assemblage of this photometer head piece is greatly simplified since the main component parts utilized in its construction are obtainable from commercial sources.