BVRI surface photometry and Fabry-Perot (Hα) 2D spectroscopy of the Magellanic-type spiral NGC 5204 are presented. While its surface brightness is typical of a normal spiral, with B_c_(O)=21.60 mag arcsec^- 2^, NGC 5204 is clearly a small system with an exponential scale length α^-1^ = 0.8 kpc. The Hα velocity field is modeled with an axisymmetrical field, using the orientation parameters derived from the photometry. A mass model with M/L = 1.8 M_sun_/L_Bsun_ for the stellar disk can account for the circular velocities V_C_(R) only out to 1.2α^-1^ (O.2R_H0_). This shows that, contrary to what is seen in more massive spirals where the dark halo has an important contribution mainly in the outer parts, the dark component of this low mass system contributes a significant amount to the mass, even in the inner parts.