Initial-boundary value problems for nonlinear dispersive equations of evolution of order 2l + 1, l ∈ N with a convective term of the form u k u x , k ∈ N have been considered on intervals (0, L), L ∈ (0, +∞). The existence and uniqueness of local regular solutions have been established.where x ∈ (0, L), Q T = (0, T ) × (0, L); l, k ∈ N; T, L are real positive numbers. This equation includes as special cases classical dispersive equations: when l = k = 1, we have the well-known Kortewegde Vries (KdV) equation, see [15,20,31], and when k = 1, l = 2, we have the Kawahara equation [5,16,23]. For k = 1, the Cauchy problem for dispersive equations of higher orders has been studied in [3,6,11,12,17,28,32] and initial boundary value problems have been studied in [4,5,7,23,30]. Although dispersive equations were deduced for the whole real line, necessity to calculate numerically the Cauchy problem, approximating the real line by finite intervals [4], implies to study initial-boundary value problems posed on bounded and unbounded intervals, [5,7,19,21,23]. What concerns (1.1) with k > 1, l = 1, called generalized Korteweg-de Vries equations, the Cauchy problem for (1.1) has been studied in [8,9,10,18,25,26], where was proved that for k = 4, called the critical case, the initial