Evidence from several countries has shown the over-representation of racial/ethnic minority groups in child protection services (CPS). The objective of the present study was to explore whether racial/ethnic and socio-economic biases influence Spanish CPS caseworkers' judgements of the severity of child maltreatment. Moreover, the study attempted to explore the influence on these judgements of the use of structured instruments and professional experience. Two case vignettes of child maltreatment were presented to 405 CPS caseworkers and 169 students of social work and psychology. Family ethnic origin and income were manipulated in the vignettes. The findings showed no statistical evidence of biases related to family ethnic origin or socio-economic status (SES) in Spanish CPS caseworkers' judgements of maltreatment severity. Biases related to family SES were found for students for the vignettes of physical abuse. CPS caseworkers and students who did not use a structured instrument to assess maltreatment severity tended to underestimate the severity for the vignettes of parental incapacity to control child/adolescent behaviour and to overestimate it for the vignettes of physical abuse. CPS caseworkers who used a structured instrument showed higher percentages of accuracy and inter-rater agreement, supporting the relevance of structured tools in reducing potential caseworkers' biases.Evidence suggests that racial/ethnic minority groups are over-represented in child protection services (CPS) and that they receive unequal treatment at different decision points (e.g. reporting, investigation and substantiation) and different services and resources compared with non-minority groups. In the USA, for example, data have consistently confirmed racial disproportionalities and disparities in CPS, particularly with regard to African-American children and families. Data have shown that compared with white families, black families are disproportionately reported and investigated for child maltreatment, over-represented in out-of-home care and moved through the system differently in terms of length and type of placement and services offered. Research has also found that the magnitude and type of disparity as well as the population for which the disparities exist vary across states, counties, population densities and neighbourhoods (Hill 2006;Fluke et al. 2011). In Canada, Aboriginal children have been found to be grossly over-represented in different phases of CPS intervention (reporting, substantiation and length of intervention) and more frequently placed in out-ofhome care (Walmsley 2005;Foster 2007), and Aboriginal, black and Latino children have been found more likely to be involved in child maltreatment investigations than white children (Lavergne et al. 2008). In Australia, indigenous children have been found more likely to be reported, investigated and substantiated for maltreatment, to receive court orders and to enter out-of-home placements than non-indigenous children (Delfabbro et al. 2010;Fallon et al. 2013). In Engla...