A rotor blade for a turbomachine, including an airfoil (1) for flow deflection, a blade root (2) for attachment to a rotor of the turbomachine, an inner platform (3) between the airfoil and the blade root, and at least one pocket (4, 5) defined by two axially spaced walls (4.1, 4.2; 5.1, 5.2) extending from the side of the platform opposite the airfoil toward the blade root. A first (4.1, 5.1) of these walls has an outer side (4.1A, 5.1A) that faces away from the pocket and, in at least one cross section perpendicular to a radial longitudinal axis of the rotor blade, slopes outwardly.