2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/203989We calculate the contribution to the anomalous magnetic moment of leptons in the type-I and type-III seesaw models. We show that, even if the scale of the new physics is pushed down to the electroweak scale, this contribution is not large enough to explain the measured discrepancy of the muon anomalous magnetic moment.13 pages, uses axodraw.sty. References added, formulas corrected, comments added, results and conclusions unchanged. Version to appear on Phys. Lett. BHigh Energy Physics - Phenomenologytext