Biopharmaceuticals like monoclonal antibodies are widely used in clinical medicine for various therapies eg, cancer, inflammatory and auto-immune diseases. Immunogenicity is one of the issues for safety. Such undesired immunogenicity can also limit the use of biopharmaceuticals, particularly for the treatment of chronic diseases that necessitate repeated treatments over long periods. Assessment of immunogenicity is an important component of drug safety evaluation, which is presently performed by estimating risk factors. Risk-based approach considers both probability of induction of immune response and expected clinical consequences. A combination of the two may result in high, medium or low risk levels and will depend on the product, patient and treatment related characteristics. Well-engineered cells, well-designed formulations coupled with good manufacturing scheme may sometimes reduce some of the extrinsic and intrinsic factors.