This thesis carried out a usability study of a software that supports cytostatic treatment of cancer patients. In this thesis the subject of research is being referred as Solunsalpaajaohjelmisto and its manufacturer as Toimittaja. The aim of the usability study was to find out how well Solunsalpaajaohjelmisto meets the needs and operating models of the healthcare professionals who use it, and whether there are differences in the answers of different users regarding the usability of the software. In addition, the thesis examined which of the application parts of Solunsalpaajaohjelmisto are the most used. An online survey was chosen as the research method for the quantitative study, and it was delivered by e-mail to the end users of the software.

There were 120 responses to the usability survey. The survey respondents were mainly nurses, doctors and pharmacists. As a result, it was concluded that Solunsalpaajaohjelmisto met the needs and operating models of the professionals who use it. Solunsalpaajaohjelmisto supported the practical work of the respondents and that the routine tasks related to the respondents' work were handled with the help of the software in a straightforward manner and without additional choices. The users of Solunsalpaajaohjelmisto also found the necessary software functions easily, and the terms and texts used in the software were primarily the same that the respondents were used to in their daily work. It was also noted that some of the users found Solunsalpaajaohjelmisto to be complicated and some felt that the software required a long and thorough induction training. The greatest strengths of the software were reducing errors and speeding up the respondent's work. The biggest weakness was perceived to be the number of clicks and transitions from one screen to another. The average school grade for Solunsalpaajaohjelmisto was 8.11 on a scale of 4 to 10.

Different respondents were grouped in this thesis based on how long the application had been used, frequency of use, profession, and the patient information system in use. When the answers to the usability survey were examined based on these factors, it was noticed that there were no significant differences regarding usability between different types of users. The defendant's profession is the only one of these that had some significance with the perceived usability of Solunsalpaajaohjelmisto, which is partly due to the differences in the job itself. To support future software development, Toimittaja now also has information on the most and least used application parts Solunsalpaajaohjelmisto. If desired, Toimittaja can use the questionnaire made in the thesis with subsequent usability studies and utilize the results of this thesis in their future software development.