Hospital healthcare service quality measurement represents an important approach for advancing healthcare systems. This paper presents preliminary results of a research on the quality of healthcare services provided by a large, public, university hospital centre in Croatia, based on the Gaps Model of Service Quality and the SERVQUAL instrument. The importance of particular service quality dimensions was analyzed, as well as the gaps between patient perceptions and expectations of healthcare services provided by 18 departments of the university hospital centre. Results revealed the gaps that exist at the level of the university hospital centre as a whole, showing the size variations in different service quality dimensions. The management of the university hospital centre should improve healthcare service quality in all dimensions by paying particular attention to the 'responsiveness' and 'tangibility', where the largest gap was identified.