The aim of this study was to evaluate efficacy of ziprasidone monotherapy for major depressive disorder (MDD) with and without psychomotor symptoms. In accordance with the sequential parallel comparison design, 106 MDD patients (age 44.0±10.7 years; female, 43.4%) were recruited and a post-hoc analysis was carried out on 12-week double-blind treatment with either ziprasidone (40–160 mg/day) or placebo, divided into two phases of 6 weeks each to the assigned treatment sequences, drug/drug, placebo/placebo, and placebo/drug. Psychomotor symptoms were evaluated on the basis of the Mini-International Neuropsychiatric Interview at baseline. Efficacy assessments, on the basis of the 17-item Hamilton Depression Rating Scale (HDRS-17) and the Quick Inventory of Depressive Symptomatology Scale, Self-Rated (QIDS-SR), were performed every week throughout the trial. In phase I, ziprasidone monotherapy produced significant improvement in patients with psychomotor symptoms compared with placebo on the basis of HDRS-17 (F=5.95, P=0.017) and QIDS-SR (F=5.26, P=0.025) scores, whereas no significant changes were found in HDRS-17 (F=2.32, P=0.15) and QIDS-SR (F=3.70, P=0.074) scores in patients without psychomotor symptoms. In phase II, ziprasidone monotherapy produced no significant differences compared with placebo. In the pooled analysis, ziprasidone monotherapy showed significance according to QIDS-SR (Z=2.00, P=0.046) and a trend toward statistical significance according to the HDRS-17 (Z=1.66, P=0.10) in patients with psychomotor symptoms. Ziprasidone monotherapy may produce significant improvement compared with placebo in MDD patients with psychomotor symptoms.