The internal phylogeny of the Ichneumonidae is investigated using parsimony analysis of a large data set including 1001 partial 28S ribosomal DNA sequences, 621 of which are newly reported, and a morphological data set of 162 characters scored variously at subfamily, tribe, genus group and genus levels and including only informative characters. The data set includes members of 630 named genera, representing all currently recognized subfamilies, all but four tribes and all but one of the taxa noted by Townes as being of uncertain placement. Sequences were aligned using clustal X, and a sensitivity analysis was performed varying gap-opening and gap-extension parameters. Alignments were appraised by reference to their ability to recover a range of traditional and morphologically recognized groups. Each alignment was analysed both independently and simultaneously with the morphological data set, and also with gap characters treated as both missing data and as informative. No single set of alignment parameters was found to be markedly better by this criterion, and different ranges of parameters led to the recovery of different recognized groups of taxa. Elision (combining all alignments into a single analysis) was therefore used, both with and without morphology and with both gap character treatments, to summarize the overall molecular signal. Analysis of the morphological matrix alone produced a number of results that are undoubtedly a consequence of convergence of morphological characters as the result of parallel evolution of similar life histories. Simultaneous analysis of the morphological data set with each of the 120 DNA alignments recovered most accepted subfamilies as monophyletic. Several currently recognized subfamilies are supported by most of the molecular analyses but some appear to be paraphyletic or polyphyletic. The Ctenopelmatinae are paraphyletic with respect to the Metopiinae. Robustly recovered results lead us to resurrect the Brachyscleromatinae to include Brachyschleroma and the Erythrodolius group of Phrudinae. The Neorhacodinae and the Phrudus group of Phrudinae are transferred to the Tersilochinae. Nonnus is transferred to the Nesomesochorinae. Hyperacmus is transferred to the Cylloceriinae. The major groupings of subfamilies that have recently been proposed (i.e. ichneumoniformes, pimpliformes and ophioniformes) were recovered as monophyletic, but their exact limits remain in question.