In order to describe the patterns of use in the open drug scene in Hamburg, a study was carried out among 616 drug users in the drug scene and in or in the vicinity of low-threshold institutions close to the drug scene in summer 2000. The special focus was on the prevalence of cocaine and crack use as well as on the utilisation of help services for drug users. 80% of the interviewed persons were male, the average age was 32.6 years. They had been using drugs such as heroin or cocaine for an average of 11 years. 84% had used heroin and 74% cocaine within the last 24 h. Use was intravenous for 66%. 57% used cocaine intravenously, the percentage of crack smokers was 22%. Compared to previous studies, an increase in cocaine use can be noted among the scene users in Hamburg, mainly related to intravenous cocaine use. Crack smoking has only increased slightly over the past few years. Based on cluster analysis, four consumption pattern groups can be established. The largest group (38%) mainly uses cocaine and heroin. The second group (26%) consists of polyvalent drug consumers using methadone in addition to heroin and cocaine, as well as, partially, benzodiazepines, cannabis or alcohol. Group 3 (19%) mainly uses heroin only, some of them also using methadone and/or cannabis. The fourth group (17%) is mainly related to alcohol, the greater part of them additionally using heroin. On the whole, it appears that those users who currently do not use cocaine (or crack) are in a better health and social situation. The group using only heroin (cluster 3) also compares favourably with the other three consumption pattern groups with regard to the intensity of use, consumption in public and risk behaviour. Almost all the interviewed persons are in contact with general practitioners. However, the increasing cocaine use has not been met by sufficient intervention and treatment programmes so far.