First, two aspects of the partiality issue are identified: (1) Is it right/reasonable for professionals to favour their clients' interests over either those of other individuals or those of society in general? (2) Are special non-universalisable obligations attached to certain professional roles? Second, some comments are made on the notions of partiality and reasonableness. On partiality, the assumption that only two positions are possible--a detached universalism or a partialist egoism--is challenged and it is suggested that partiality, e.g. to family members, lies between these two positions, being neither a form of egoism, nor of impersonal detachment. On reasonableness, it is pointed out that 'reasonable' is an ambiguous concept, eliding the notions of the 'morally right' and the 'rational.' Third, a series of practical examples are taken from counselling, medicine, law, education and religious practice and some common principles are abstracted from the cases and discussed. These include truth-telling, confidentiality, conflicts of interest between clients and particular others and between clients and society. It is concluded that while partiality can be justified as a useful tool in standard cases, particular circumstances can affect the final verdict.