Red pandas are able to reproduce at around 18 months of age, and are fully mature at two to three years. Mating season for red pandas is from mid-January to early March.
A few days before birth, females begin to collect material, such as brushwood, grass, and leaves, to build a nest, which is normally located in a hollow tree or a rock crevice.

Gestation period of red pandas is between 112 to 158 days. The female gives birth in mid-June to late July to one to four blind and deaf cubs weighing 110 to 130 grams.

After birth, the mother cleans the cubs, and can then recognize each by its smell. At first, she spends 60% to 90% of her time with the cubs. After the first week, the mother starts spending more time outside the nest, returning every few hours to nurse and groom the cubs. She moves the young frequently among several nests, all of which she keeps clean. The cubs start to open their eyes at about 18 days of age. By about 90 days, they have achieved full adult fur and coloring, and begin to venture out of the nest. They also start eating solid foods at this point, weaning at around six to eight months of age. The cubs stay with their mother for around 1 year, until the next litter is born in the following summer.