Healthcare is a technology-intensive area where all the healthcare organizations use an information system. Managing daily works and providing the continuity of healthcare is impossible without healthcare information systems. Healthcare information systems have to be well supported and managed, also have to be improved to meet the changing needs, they must be living systems. In this respect, evaluations are carried out to reveal the weak and strong sides of information systems in operation. Evaluation is an important subject for medical informatics domain. The investors and managers need to know the success level and poor sides of their information system to make improvements. In this sense, a case study is performed in this study, to evaluate a healthcare information system. Particularly, the recently deployed laboratory information system (LIS) is evaluated by means of questionnaires, applied to both patients and users of the laboratory information system. Laboratory information system is evaluated on the basis of Function sufficiency, Decreasing Work Load, Speed, Learning Ease, Improving Service Quality, Availability, Help Manuals, User Satisfaction, and Patient Satisfaction features. The features needing to be improved in terms of the effectiveness and efficiency of LIS are measured based on the threshold value. The results are presented in a variable table according to the threshold value selected by the evaluator. As the target threshold value increases, the number of features needing to be improved also increases. Sağlık Bilgi Sistemlerinin zayıf yönlerinin belirlenmesi: Bir Deneysel Esağlık Değerlendirme Çalışması ÖZ Sağlık sektörü, tüm sağlık teşkillerinin bir bilgi sistemi kullandığı teknoloji-yoğun bir alandır. Sağlık hizmetinin devamının sağlanması ve günlük sağlık bakımı işlemlerinin yürütülmesi sağlık bilgi sistemleri olmaksızın imkansız bir hale gelmiştir. Sağlık bilgi sistmleri sürelki