BACKGROUND A stereotactic computer with a mechanical, proprioceptive arm was acquired in 1996. The aim of this report is to review the 4-year experience with frameless, computer-aided stereotaxy in a small neurosurgical department. METHODS From 1996 to 1999 the computer was used for 121 operations. The surgical files from these operations were either retrospectively or prospectively registered. Patient and computer data, type of surgery, complications and number of surgeons were noted. The versatility, benefits, and drawbacks of the stereotactic computer were evalued based on these findinos. RESULTS Seven surgeons performed a total of 121 computer-assisted operations. The procedures consisted of 63 stereotactic tissue samplings, 44 craniotomies, 7 abscess punctures and 3 insertions of intracerebral devices (shunts and microelectrodes). Technical complications were seen in 6 cases (4.8%), but this did not affect the surgical outcome. CONCLUSIONS The stereotactic computer has enabled the department to broaden its spectrum of procedures. High precision surgery such as stereotactic biopsy has been possible without the use of a framebased system. The results indicate that even small neurosurgical units with a limited number of procedures can safely and successfully implement neuronavigation in daily routines. (C) 2002 by Elsevier Science Inc.