Conformal invariant new forms of p-brane and Dp-brane actions are proposed, The field content of these actions are: an induced metric, gauge fields, an auxiliary metric and an auxiliary scalar field that implements the Weyl invariance, This scaler field transforms with a conformal weight that depends on the brane dimension. The proposed actions are Weyl invariant in any dimension and the elimination of the auxiliary metric and the scalar field reproduces the Nambu-Goto action for p-branes and the Born-Infeld action for Dp-branes, As a consequence of the fact that in the p-brane case, the action is quadratic in partial derivative (0)X, we develop a complete construction for the associated canonical formalism, solving the problem in previous formulations of conformal p-brane actions where the Hamiltonian can not be constructed, We obtain the algebra of constraints and identify the generator of the Weyl symmetry, In the construction of the corresponding supersymmetric generalization of this conformal p-brane action we show that the associated K-symmetry is consistent with the conformal invariance, In the Dp-brane case, the actions are quadratic in the gauge fields. These actions can be used to construct new conformal couplings in any dimension p to the auxiliary scaler field now promoted as a dynamical variable, (C) 2001 Published by Elsevier Science B.V.