The semi-detached eclipsing binary system CF Puppis (P=7.65 days) has been analysed using the Wilson-Devinney program. Light curves have been obtained in the GENEVA 7-colour photometric system, and radial velocity curves for both components have been measured with the cross-correlation technique. The physical and orbital parameters have been determined through a self-consistent simultaneous solution of light curves in seven colours and of the radial velocity curves of both components. The absolute elements of the components are, for the primary (mass gainer), M-1=1.84+/-0.04 M-circle dot, R-1=3.06+/-0.01 R-circle dot, M-bol1=1.74+/-0.02, T-eff1=6671+/-27 K, and for the secondary (mass loser), M-2=0.38+/-0.01 M-circle dot, R-2=5.39 R-circle dot, M-bol2=2.51+/-0.02, T-eff1=4202+/-17 K. The semi-major axis A of the relative orbit is 21.28+/-0.15 R-circle dot. The estimated spectral types of the components are about F3 IV (primary) and K2/3 III. CF Pup has one of the coolest component A among the Algol systems. The equatorial rotational velocities are 24.8 (primary) and 37.0 km s(-1). The secondary is clearly synchronized, and the primary is nearly synchronized (v(syn)=20.2 km s(-1)). The distance to CF Pup is evaluated to 506+/-16 pc, and the colour excess E[B2-V1] to 0.033+/-0.017. (C) 2003 Elsevier B.V. All rights reserved.