Objectives: To evaluate the efficacy of vibroacoustic stimulation (VAS) and modified fetal biophysical profile (mFBP) for early intrapartum fetal assessment and prediction of adverse perinatal outcome. Methods: In this prospective study, 210 women who were in latent phase of labor at the time of admission to the labor unit were subjected to VAS/mFBP, in which fetal startle response and fetal heart acceleration under combined B/M mode ultrasonography following VAS were observed. The results of VAS/mFBP were correlated with adverse perinatal outcome. Standard "fourfold" format was used to calculate various diagnostic values. Results: Mean testing time was 4.86+0.72 min. Of the 210 fetuses subjected to VAS/ mFBP, 200 (95.2%) were reactive and 10 (4.8%) nonreactive. There were 198 (94.3%) favorable and 12 (5.7%) adverse perinatal outcomes. VAS/mFBP had: sensitivity 66.7%, specificity 99.0%, positive predictive value 80.0%, negative predictive value 98.0%, and accuracy 97.2%. Conclusions: Because of its simplicity, ease of administration, short testing time, noninvasiveness, and high accuracy VAS/mFBP for early intrapartum fetal assessment is a reliable diagnostic approach.