The Christo Inventory for Substance-misuse Services (CISS) was developed as a single page outcome evaluation tool completed by drug/alcohol service workers either from direct client interviews or from personal experience of their client supplemented by existing assessment notes. Its 0-20 unidimensional scale consists of 10 items reflecting clients' problems with social functioning, general health, sexual/injecting risk behaviour, psychological functioning, occupation, criminal involvement, drug/alcohol use, ongoing support, compliance, and working relationships. Comparison scores indicating low, average or high problem severity were produced by 243 drug users attending a harm minimisation out patient service and 102 alcohol users at an outpatient alcohol service. Means and cut-off scores for abstinence oriented treatments were derived from a 6-month follow-up of 90 treated drug users. Sub sets of the harm minimisation sample were used to derive item alpha, test-retest and inter-rater reliability coefficients of 0.74, 0.82 and 0.82, respectively. The inter-rater coefficient increased to 0.91 when retests were conducted the same day. Among the abstinence oriented treatment sample the CISS produced correlations ranging from 0.43 to 0.99 with the Opiate Treatment Index and measures of trait anxiety, unpleasant life events, poor quality of life and low self-esteem. The simplicity, flexibility and brevity of the CISS make it a useful tool allowing comparison of clients within and between many different service settings.