Purpose: To determine the intraocular lens (IOL) rotational stability depending on patient position in the first postoperative hour after femtosecond laser assisted cataract or refractive surgery with implantation of a non-toric IOL in the capsular bag. Setting: Department of Ophthalmology, Goethe-University, Frankfurt, Germany. Design: Prospective, randomized clinical trial. Methods: In this study, 38 eyes of 36 patients received femtosecond laser assisted phacoemulsification and implantation of a non-toric IOL in the capsular bag. Patients were randomized into two groups: patients laid down for one hour after surgery due to the clinical standard (LD group), patients walked around in the first postoperative hour (W group). No miotic eye drops were applied at the end of operation. A retroilluminated slit lamp picture was taken at the end of the operation (baseline), one hour and one day postoperative. Changes in IOL position were measured by an axis between two episcleral landmarks and the haptics of the IOL. Measurements were performed by an image processing application specified for medical and scientific purpose. If not normally distributed, the paired t-test was used. Otherwise, the Mann-Whitney-U-Test was used if data was not normally distributed. Results: IOL rotation in the first hour was 1.80° ± 1.80° in the LD group and 1.21° ± 2.11° in the W group (p=0.123). One day after operation, IOL position differed from the baseline measurement with 1.52° ± 1.89° in the LD group and 1.51° ± 1.69° in the W group (p=0.773). Conclusion: Early postoperative patient position does not seem to influence IOL rotational stability.