Advances in antibody engineering have solved many of the problems inherent in traditional sources of antibodies, and about a quarter of all biotechnology-based drugs now in development are antibodies. This has come at a time when it is apparent that reliance on antibiotics alone is beginning to select out resistant pathogens, fungi being a prime example. The development of antibody-based therapeutics, such as Mycograb, against novel fungal targets offers a new approach to combating the spread of resistance and reducing mortality.