This work presents psychometric analyses on the Early Memories of Warmth and Safeness Scale, which intends to evaluate the subjective perception of ones' early rearing experiences. Factor structure, measurement invariance, latent mean comparisons and validity in relation to external variables (i.e., forms of self-criticism/self-assurance, experiential avoidance and depressive, anxious and stress symptoms) were investigated. A sample of 1464 adolescents (52.3% male adolescents, mean age = 16.16, standard deviation = 1.51) was used, including 1064 participants recruited from schools, 192 participants recruited from foster care facilities and 208 boys recruited from juvenile justice facilities. A shortened version of the scale was also developed and subjected to the same psychometric analyses. A one-factor measurement model was a good fit for the data taken from both the complete and brief versions of the instrument. Such measures showed to be internally consistent with alpha values higher than 0.89. Evidence for their construct validity in relation to external variables was also found, with correlation values ranging from 0.19 to 0.45 for the complete version and from 0.18 to 0.44 for the brief version of the instrument. The brief version was the only one proving to be gender and sample invariant. Boys and girls scored similarly in their account of early memories, whereas community boys presented significantly higher scores when compared with referred and detained boys. Thus, the brief version of the instrument may be an appropriate alternative for use with diverse adolescent samples and may serve to advance knowledge on how early experiences impact on psychopathological outcomes. Copyright (C) 2016 John Wiley & Sons, Ltd.