<p>Adequate assessment of parenting quality depends on an acceptable understanding of parental involvement as well as faithful comparison of parenting patterns of fathers and mothers. To advance this understanding and assessment, the objective of the present study was to investigate the psychometric properties of the Inventory of Father and Mother Involvement (IFMI) items. To this end, mothers (<i>n</i> = 728) and fathers (<i>n</i> = 516) from 22 Brazilian states responded to the IFMI and to a Sociodemographic Questionnaire. Rating Scale Model was used to assess the psychometric properties of the items. Initially, results led to a reduction of the number of response categories of the instrument’s response scale. After adjustment, it was found that the IFMI more accurately measures parental involvement of intermediate quality, presenting adequate infit, outfit and reliability indices. Regarding gender bias analyzes, results of the Differential Item Functioning analysis showed that all items of the instrument are equally difficult for fathers and mothers to endorse. Taken together, evidence obtained confirms the potential use of the IFMI both for the individual assessment of the quality of parental involvement of fathers and mothers, as well as for the comparison of these patterns between genders.</p>