Aim: This study was conducted to investigate the effectiveness of two types of mattresses with different support surfaces used in bedridden patients.

Method: The sample of this quasi-experimental study consisted of 60 patients according to the inclusion criteria. A group I and group II of 30 patients each were formed from the sampled patients. For the patients in group I, a bed with a cube/block system and vibration (massage) feature was used. For the patients in group II, a viscoelastic mattress was used. The data of the study were collected with the ''Patient Identification Form'', ''Braden Scale'', ''Pressure Wound Observation Form'' and ''Wound Measurement Chart''. Number-percentage distributions, Chi-square, Fisher's Exact Probability Test and Mann-Whitney-U tests were used to evaluate the data.

Implications for Clinical Practice: It was determined that the support surface used affected the pressure sore size and the mattress with cube/block system and vibration (massage) feature created smaller sized wounds in the sacrum, trochanter, malleolus and heel regions. In the sacrum, scapula, and heel regions, although not statistically significant in terms of wound stage and the number of patients who developed pressure sores, it was seen that the mattress with cube/block system and vibration (massage) feature was more effective.

Inclusion Criteria:

• A "low risk" rating on the Braden Scale.
• Voluntary informed consent from conscious patients and consent from the legal guardian for unconscious or confused patients.
• Absence of pressure sores upon admission to the clinics.
• A BMI (Body Mass Index) not exceeding 30.00 (as classified by the World Health Organization).

Exclusion Criteria:

• The patient's bed was changed in less than ten days after inclusion in the study,
• Patient referral,
• Discharge
• Exhitus was the exclusion criteria.