Photodiodes fabricated from conjugated polymers exhibit excellent sensitivity to visible‐UV radiation. The photosensitivity increases with reverse bias voltage. The photoresponse of diodes fabricated from poly(3‐octyl thiophene) is relatively flat in the visible and near UV; for wavelengths shorter than 550 nm, the absolute sensitivity is greater than 0.3 A/W under reverse bias of 15 V, larger than that of commercial UV‐enhanced Si photodiodes. Photodiodes made from poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene], MEH‐PPV, sensitized with C60, show similar sensitivity. The ease of fabrication into large size, arbitrary shapes, and even onto flexible substrates makes the polymer photodiode a novel photodetector with potential for use in a wide range of applications.