Forensic testing for drugs of abuse in hair has become a useful diagnostic tool in determining chronic drug use as well as examining long-term drug history thorough segmental analysis. However, sensitive and specific analytical methods are needed. A simple, rapid and highly sensitive and specific method for the extraction and quantification of 33 opioids, opiates, cocaine, and amphetamines is presented. The method was fully validated according to international guidelines. Twenty milligrams of hair sample was pulverized and then incubated in the same disposable tube with methanol (under sonication at 45°C) during 4h. After centrifugation the supernatant was evaporated up to about 100 μL and a solid phase extraction (SPE) followed by separation and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UHLC-MS/MS) were carried out. Chromatographic separation was achieved using a BEH phenyl column eluted with 0.1% formic acid: methanol (0.1% formic acid). Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions. Good intra-assay and inter-assay precision (relative standard deviations (RSDs) were observed (<15%) for most of the compounds. The lower limit of quantification was fixed at the lowest calibrator in the linearity experiments and it ranged from 0.006 to 0.063 ng/mg. No instability was observed in processed samples. Extraction efficiency varied from 37 to 107% (except for EDDP with a recovery of 5%) and matrix effects ranged from 52 to 160%, and for most of the compounds it was compensated by the internal standard (IS). The method was subsequently applied to authentic hair samples obtained from forensic and toxicology cases and to proficiency test (obtaining z-scores lower than 1 for most of the compounds). The validation and actual sample analysis results show that this method is rugged, precise, accurate, and well-suited for routine hair analysis.