Two sets of ostrich eggs (60 and 120 eggs) were imported into the United Kingdom under class 1 quarantine restrictions. Single stage incubation was carried out and the eggs were weighed before and during incubation in order to control weight loss. In the two hatches the weight losses during the incubation of viable eggs were 13.4 per cent and 11.4 per cent, respectively. The development of the eggs was followed by candling and although only dark shadows were observed a pattern could be recognised. For the first set of eggs the average length of incubation was 45.9 days with an interval of 12.7 hours between pipping and hatching. The second set of eggs was incubated at higher temperatures than the first and the main incubation period was 43.3 days with hatching 19.2 hours after pipping. Larger eggs took longer to hatch.