Purpose: The Index of Dental Anxiety and Fear (IDAF-4C+) constitutes a theory-grounded, reliable and valid instrument, which, due to its modular structure, allows different uses such as assessing dental anxiety levels, establishing preliminary dental phobia diagnoses and identifying feared stimuli. This study aimed to develop a Spanish version of the original IDAF-4C+ and evaluate its psychometric properties. Materials and Methods: A sample of 231 Spanish undergraduate students (70.6% female; mean age 21.4 years) completed a questionnaire comprising the Spanish version of the IDAF-4C+ and other measures related to dental anxiety. The structure, reliability and validity of the adapted IDAF-4C+ were analysed. Results: The adapted IDAF-4C fear module yielded a single-factor structure and demonstrated good internal consistency (Cronbach's alpha) and test-retest reliability. It shared a greater amount of variance with phobia diagnoses than the Modified Dental Anxiety Scale (MDAS) and a single-item measure of dental fear (SIDF). Moreover, the IDAF-4C was moderately to highly correlated with the MDAS and the SIDF measure, as well as with variables connected with dental anxiety such as negative dental thoughts, having had a negative dental experience and negative affect. The frequency of dental visits was also linked to IDAF-4C scores, and IDAF-stimulus items involving cognitive vulnerability, interpersonal and cost concerns were associated with dental attendance. Conclusion: The Spanish version of IDAF-4C+ presents similar psychometric properties to the original version which, considering the advantages of this instrument, qualifies the adapted one for its use in different research and applied contexts. Keywords: assessment, dental anxiety and fear, dental phobia, dental visits