We have measured the electrical resistivity and ac magnetic susceptibility χ(T) of (La1-xCex)3Al, for 0<~x<~1, and the electrical resistivity of (Ce1-zYz)3Al, for 0<~z<~0.1. The system was characterized using x-ray diffraction and metallography. From x-ray data we were able to determine the structure for all samples to be hexagonal and that the unit-cell volume decreases linearly in going from the La-rich side to the Ce-rich side. The results show that La3Al is a superconductor below 6.2 K and that Tc decreases rapidly with the increase of the Ce concentration. For x>0.04 we observed a minimum in the resistivity and a reduction of the effective magnetic moment of Ce due to a strong compensation promoted by the Kondo effect. Our results show that the Kondo temperature increases with Ce and Y concentration, according to the reduction of the unit-cell volume. We also show that the antiferromagnetic transition temperature goes through a maximum at z=0.025, indicating that there is an interplay between superconductivity, antiferromagnetic ordering, and the Kondo effect. A diagram illustrating the evolution of the TK and TN is presented. The electronic specific heat (γ) increases with the Ce concentration showing a maximum around x≈0.4. It was also possible to determine values for the ρJ product and the relative variation of the exchange parameter.