In this paper we present new results on sequential and parallel construction of optimal and almost-optimal length-restricted prefix-free codes. We show that length-restricted prefix-free codes with error 1/nk for any k > 0 can be constructed in O(n log n) time, or in O( log n) time with n CREW processors. A length-restricted code with error 1/nk for any k ≤ L/ log Φ n, where [Formula: see text], can be constructed in O( log n) time with n/ log n CREW processors. We also describe an algorithm for the construction of optimal length-restricted codes with maximum codeword length L that works in O(L) time with n CREW processors.