I am working fast .We conducted a study to evaluate speech recognition software in an otorhinolaryngology unit and to assess its impact on productivity prior to general implementation. Current speech recognition software (IBM ViaVoice, version 10) was implemented on a personal computer with a 2-GHz central processing unit, 256 MB of RAM, and a 30-GB hard disk drive, with and without add-on professional vocabulary for otorhinolaryngology. This vocabulary was added by the automated analysis of an additional 12,257 documents from our department. We compared the word recognition error rates for three different text types and determined their impact on the amount of surgeon's time that was invested in the production of an error-free document. Although error rates without any professional vocabulary database were rather high (operation reports: 38.72%; consultation notes: 27.77%), the patient information was edited with a satisfactory result (10.65%). Best results were obtained with the specialty-related vocabulary database added by the analysis of our own documents (operation reports: 5.45%; consultation notes: 5.21%). An increase in productivity compared with that of conventional transcription was found at an error rate of less than 16%.