The phylogenetics and higher (family-group) classification of extant members of the beetle family Dytiscidae (Coleoptera), or predaceous diving beetles, is reviewed and reassessed. A phylogenetic analysis of the family is presented based on 168 species of diving beetles and 9 outgroup taxa from Gyrinidae, Noteridae, Amphizoidae, and Paelobiidae. All currently recognized dytiscid subfamilies and tribes are represented, most by multiple genera and species. Data include 104 morphological characters and approximately 6700 aligned bases from 9 DNA sequence fragments from cytochrome c oxidase I (COI) and II (COII), histone III (H3), 16S rRNA (16S), 12S rRNA (12S), arginine kinase (argkin), RNA polymerase II (RNA pol II), elongation factor 1 alpha (Ef1α), and wingless (wnt). Parsimony and Bayesian analyses were conducted. The topology of the parsimony tree (consensus of 13 equally-parsimonious solutions) exhibits numerous anomalies inconsistent with convincing morphological features and the Bayesian results and has, generally, relatively poor bootstrap support for major clades. The Bayesian topology is more consistent with major morphological features and has strong support for most clades, and conclusions are based primarily on this estimate. Major higher-level phylogenetic relationships with strong support include: (1) monophyly of Dytiscidae Leach, (2) Matinae Branden sister to the rest of Dytiscidae, (3) Agabinae Thomson + Colymbetinae Erichson, (4) Hydrodytinae Miller + Hydroporinae Aubé, (5) Dytiscinae Leach + Laccophilinae Gistel + Cybistrini Sharp + Copelatinae Branden, (6) monophyly of the subfamilies Matinae, Colymbetinae, Copelatinae, Coptotominae Branden, Lancetinae Branden, Laccophilinae (including Agabetes Crotch), Agabinae (support weaker than in other subfamilies) and Hydroporinae (monophyly of Hydrodytinae not tested), (7) paraphyly of Dytiscinae with Cybistrini sister to Laccophilinae (with strong support) and this clade sister to other Dytiscinae, and (8) monophyly of both Agabini (Agabus-group of genera) and Hydrotrupini Roughley (Hydrotrupes Sharp and the Platynectes-group of genera). Major conclusions regarding tribes within Hydroporinae include: (1) monophyly of the tribes Vatellini Sharp, Methlini Branden, Hydrovatini Sharp, Hygrotini Portevin, Hyphydrini Gistel (without Pachydrus Sharp) and Bidessini Sharp (including Peschetius Guignot, Hydrodessus J. Balfour-Browne and Amarodytes Régimbart) (monophyly of Laccornini Wolfe and Roughley and Pachydrini Biström, Nilsson and Wewalka not tested), (2) Pachydrini is a problematic, long-branched taxa resolved here as sister to Hydrovatini but with weak support, (3) Hydroporini monophyletic except for Laccornellus Roughley and Wolfe and Canthyporus Zimmermann, (4) Laccornellus and Canthyporus together monophyletic and sister to Hydroporinae except Laccornini. Four groups are resolved within Hydroporini exclusive of Laccornellus + Canthyporus corresponding to the Deronectes-, the Graptodytes-, the Necterosoma- and the Hydroporus-groups of genera. The classification of Dytiscidae is revised with the following taxonomic changes : (1) Hydrotrupini is recognized as a tribe of Agabinae including the genus Hydrotrupes and the Platynectes-group of genera, (2) the genus Rugosus García is moved from Colymbetinae to Copelatinae, (3) Cybistrini is elevated from tribe rank within Dytiscinae to subfamily of Dytiscidae, (4) Hyderodini Miller is placed as a junior synonym of Dytiscini, (5) Laccornellus and Canthyporus are removed from Hydroporini and placed in their own tribe, Laccornellini, (6) the following family-group names are resurrected from synonymy with Hydroporini and placed as subtribes within Hydroporini, Deronectina Galewski (for the Deronectes-group of genera), Siettitiina Smrž (for the Graptodytes-group of genera), Sternopriscina Branden (for the Necterosoma-group of genera), and Hydroporina (for the Hydroporus-group of genera), (7) Carabhydrini Watts is placed as a junior synonym of Sternopriscina, and (8) Hydrodessus, formerly incerta sedis with respect to tribe, is placed in Bidessini. Each subfamily, tribe and subtribe is diagnosed and its taxonomic history discussed.