Background: Neonatal enterovirus sepsis has high mortality. Antiviral therapy is not available. Methods: Neonates with suspected enterovirus sepsis (hepatitis, coagulopathy, and/or myocarditis) with onset at ≤15 days of life were randomized 2:1 to receive oral pleconaril or placebo for 7 days. Serial virologic (oropharynx, rectum, urine, serum), clinical, pharmacokinetic, and safety evaluations were performed. Results: Sixty-one subjects were enrolled (43 treatment, 18 placebo), of whom 43 were confirmed enterovirus infected (31 treatment, 12 placebo). There was no difference in day 5 oropharyngeal culture positivity (primary endpoint; 0% in both groups). However, enterovirus-infected subjects in the treatment group became culture negative from all anatomic sites combined faster than placebo group subjects (median 4.0 versus 7.0 days, P =.08), and fewer subjects in the treatment group remained polymerase chain reaction (PCR)-positive from the oropharynx when last sampled (23% versus 58%, P =.02; median, 14.0 days). By intent to treat, 10/43 (23%) subjects in the treatment group and 8/18 (44%) in the placebo group died (P =.02 for 2-month survival difference); among enterovirus-confirmed subjects, 7/31 (23%) in the treatment group died versus 5/12 (42%) in the placebo group (P =.26). All pleconaril recipients attained concentrations greater than the IC90 after the first study day, but 38% were less than the IC90 during the first day of treatment. One subject in the treatment group and three in the placebo group had treatment-related adverse events. Conclusions: Shorter times to culture and PCR negativity and greater survival among pleconaril recipients support potential efficacy and warrant further evaluation.