<p>This study examines the impact of blood pressure measurement in different postures on diastolic and systolic blood pressure values, as well as anxiety levels, in pregnant women diagnosed with preeclampsia. The study was conducted between March and June 2024 as a quasi-experimental pretest-posttest study with 96 pregnant women diagnosed with preeclampsia who were hospitalized in the perinatology unit of a training and research hospital. Data were collected using a descriptive information form and the State Anxiety Scale. Among the participants in the study, a statistically significant difference was found between systolic blood pressure measured in the fully seated posture and that measured in the left and right lateral postures (p &lt; 0.001). Regarding diastolic blood pressure, a significant difference was observed among the values measured in the left lateral, right lateral, and semi-Fowler postures (p &lt; 0.001). The left and right lateral postures were found to have a lowering effect on systolic blood pressure. Additionally, a statistically significant difference was detected in the State Anxiety Scale scores of participants before and after blood pressure measurement in the left lateral posture (p &lt; 0.05). In pregnant women with preeclampsia, the left and right lateral postures were found to lower both systolic and diastolic blood pressure compared to the sitting posture. Additionally, the left lateral posture was effective in reducing anxiety levels. Therefore, conducting blood pressure measurements in the left lateral posture in clinical practice may yield more optimal results for pregnant women with preeclampsia.</p>