There is tension within Child and Adolescent Mental Health Services (CAMHS) assessments between the richness of differing practitioner's perspectives and maintaining a basic level of assessment that is acceptable to all disciplines. Standardized assessments are mandatory in research, yet are rarely applied systematically across CAMHS.The use of standardized assessments in routine practice might aid the allocation of families to the practitioners best able to meet their needs and free up time for intervention. However, practitioners' attitudes towards standardized assessment will dictate the success of such an approach. Fifty practitioners working in two CAMHS completed semi-structured interviews that explored their attitudes towards the use of standardized assessments in clinical practice, which were analysed using thematic analysis. Practitioners could identify both advantages and disadvantages of the routine use of standardized assessment. While they valued standardization, opportunities for service organization and increased information, some expressed concerns related to the choice, accuracy and influence of measures, as well as labelling. Almost one-third complained about their lack of pre-registration training in working with children, let alone their assessment. Practitioners, clinicians and policy makers need to consider these issues if they wish to introduce standardized assessments into routine practice. Senior staff need to be aware how unskilled some junior practitioners feel when they start working in CAMHS and offer appropriate support and supervision.