Purpose: The study of the attitude of Health Professionals of the General Oncology Hospital of Attica towards the integrated Hospital Information Systems (HISs) as well as of the socio-demographic factors that shape it. Material-Method: A stratified sampling quantitative survey was conducted using the occupational category of the employees as the stratification variable. Data were collected by employing the standard Nurses Attitudes towards Computerization (NATC) self-report questionnaire. Statistical analysis was conducted with the use of the statistical data processing SPSS-v25 software. Results: The staff of the General Oncology Hospital under study have a positive attitude towards the use of Hospital Information Systems (Mean = 3.73, SD. = 0.54). Statistically significant differences between occupational categories were found only for the dimension of “Providing quality care to the patient” (p = 0.007) and more specifically among nurses and doctors. Regarding the effect of demographic factors on the five dimensions that form the attitude of health professionals towards the HIS, only “gender” (p = 0.009) and “occupation categories” (p = 0.007) seem to influence this attitude and specifically the dimension “Providing quality care to the patient”, whereas “previous experience in use of computers at work” affects the dimension “Reduction in jobs” (p = 0.009). Conclusions: The statistical analysis of the data showed that the employees of the General Oncology Hospital under study have a positive attitude towards the use of the integrated Hospital Informatics Systems (HISs). Males tend to have the most positive attitude while employees who already make use of personal computers in their work, tend to disagree with the view that HIS will lead to a job reduction.