This invention relates to a system and method for monitoring the cold chain integrity of at least one packet of environmentally sensitive goods. The system comprises a monitoring unit applied directly to the goods packet, the monitoring unit comprising an environmental sensor monitoring an environmental condition to which the goods are subjected to and an optical output device for conveying environmental condition data. The system further comprises a camera operable to capture the environmental condition data conveyed by the optical output device, a memory for storing the environmental condition data captured by the camera and a processor for analyzing the environmental condition data. The use of a camera allows for a very simple, robust and inexpensive optical output device (e.g. an LED) to be used. The arrangement reduces the equipment cost significantly thereby allowing application across a wider range of products and provides greater flexibility and possibility for analyzing the cold chain integrity.