SUMMARYA survey of in vitro and in vivo sensitivity of Pythuim aphanidermatum to several commercial fungicides and a biofungicide was undertaken. An isolate of P. aphanidermatum pathogenic to pepper was collected from a naturally infested greenhouse soil from Smederevska Palanka, Serbia. The P. aphanidermatum isolate was sensitive to all tested products. The obtained EC 50 values were as follows: 10.21 mg/l for propamocarb-hydrochloride, 302.65 mg/l for fosetyl-Al, 11.18 mg/l for mancozeb, 1.27 mg/l for mefenoxam, 0.05 mg/l for azoxystrobin, and 175.33 mg/l for tea tree oil. Under greenhouse conditions, fosetyl-Al was the most efficient fungicide among the tested substances (97.5%). The biofungicide tea tree oil (Timorex Gold) (35.0%) exhibited the lowest efficacy among the tested materials, but it was still significantly better than the untreated control plot. The efficacies of propamocarb-hydrochloride (Previcur 607 SL), mancozeb (Mankogal 80 WP), azoxystrobin (Quadris) and mefenoxam (Ridomil gold 480 SL), were 72.5%, 77.5%, 57.5% and 75.0%, respectively.