Charge transport and magnetic properties of the perovskites LaMnO3+delta, as well as La1-yMnO3-(3y/2+delta) with 0 less than or equal to y less than or equal to 0.15 and LaMn1-zO3-(3z/2+delta) with 0 less than or equal to z less than or equal to 0.10 have been studied as a function of the nonstoichiometry, delta, and a tentative magnetic phase diagram of the system LaMnO3+delta is proposed. Depending on delta, magnetically inhomogeneous phases with either an antiferromagnetic or a ferromagnetic matrix phase are formed below the magnetic ordering temperature, For delta greater than or equal to 0.14, a transition from localized to itinerant charge carriers is observed below T-c.