In 2012, the biological effi cacy of the fungicide mixture pyraclostrobin + boscalid (Signum®, BASF ) in the control of two economically most important disease of lettuce, gray mold (B. cinerea ) and downy mildew (B. lactucae ), was tested. The experiments were conducted at the location of Belgrade (Ledine, Iceberg, salat center), and Smederevska Palanka (Experimental fi eld of the Institute of Vegetable Crops), by type of randomized block design with four replications (EPPO, 1997). Fungicide application was performed by a sprayer SOLO 423 with consumption of 400 l of water ha-1. A fungicide Signum®, (a.i. pyraclostrobin + boscalid) was applied in a dosage of 1.5 kg ha-1 and was carried out a total of four treatments of the growth stages starting when the plants had developed three leaves (BBCH 13). As the standard products at both locations the fungicide Sumilex SC 50 (a. i. procymidone), in the case of B. cinerea, and Ridomil MZ (a.i. metalaxyl + mancozeb), in the case of for downy mildew, were used. After manifesting clear distinguish between treated and untreated (control) plots, assessment of disease severity (60 plants per plot) and efficiency of fungicides were calculated. The fungicide mixture pyraclostrobin + boscalid, tested in this study, showed a high efficacy against downy mildew of lettuce, which amounted to 93.6 % (Location: Belgrade - Ledine) and 97.4 % (site: Smederevska Palanka) respectively. The effi ciency of the tested fungicide combination of suppression of gray mold was 92.5 % (location: Belgrade - Ledine) and 93.5 % (site: Smederevska Palanka), respectively.