In this talk, we expand our research on the stability limit of two equal-mass planets in a horseshoe (coorbital) configuration and consider non-circular orbits. Through numerical simulations, we test the long term stability (up to 100 Myrs) of an arrange of two equal-mass planets with planet-to-star mass ratio ranging from 10-4 to 5×10-2 and initial period ratio between 1 and 1.1 (with a ~ 1 au). In this occasion, we also investigate the effect of three different initial eccentricities (i.e., e = 0, 0.01 and 0.1) and two initial relative mean longitudes (dl = 60° and 180°) on the stability of these systems. Among other parameters, we calculate and analyze the coorbital period of the stable realizations; this period has a functional form which differs between the tadpole and horseshoe configurations, as discussed in this talk. Finally, we find that the upper mass stability limit for horseshoe planets varies with the eccentricity, respectively for e = 0.0, 0.01 and 0.1, the maximum mass stability limits are 2.5×10-3 Msun, 1×10-3 Msun and 5×10-4 Msun, regardless of the initial relative mean longitude.