The purpose of this research project was to construct and validate an instrument to assess Emotional Dependency. The population sample was taken from the Metropolitan Area of Medellin (Colombia) and consisted of 815 participants, of which 506 (62.1%) were women and 309 (37.9%) were men, between the ages of 16 and 55 years old. The original questionnaire contained 66 items, and by means of a factor analysis test,43 of them were excluded for not complying with the selection criteria. Thus, the fi nal questionnaire consisted of 23 items and six factors. The Cronbach Alpha score for the total scale was 0.927, which explained 65% of the variance, whereas for each specifi c factor the Alpha Scores obtained were the following: Factor 1: Separation Anxiety (7 items, α = 0.87); Factor 2: Couple’s Affective Expression (4 items, α = 0.84); Factor 3: Change of Plans (4 items, α = 0.75); Factor 4: Fear of Loneliness (3 items, α = 0.8); Factor 5: Borderline Expression (3 items, α = 0.62), and Factor 6: Attention seeking (2 items, α = 0.7.8). Signifi cant differences related to gender were found in the different subscales. The highest scores for the female population were obtained in Factors 2 and 4, Couple’s Affective Expression and Fear of Loneliness, whereas men reported higher scores in Factor 6: Attention Seeking. With respect to age, it was found that the highest scores corresponded to the subscales Change of Plans and Borderline Expression in the Adolescent