Aim <p>Developing a measurement tool to determine digital dementia is an important step toward understanding the prevalence and effects of digital dementia. The present study aimed to develop the “Digital Dementia Scale Adult Form” to determine digital dementia in individuals aged 18 and over by examining the concept of digital dementia.</p> Methods <p>The form which consisted of 22 statements with proven validity in terms of language and psychometrics was applied to 615 individuals. Exploratory and confirmatory factor analysis was used to determine the construct validity, and a 27% lower-upper group comparison was made to determine the internal validity</p> Results <p>The “Digital Dementia Scale Adult Form” consisted of 3 subdimensions and 15 items and could explain 65.7% of the total variance as a 5-point Likert-type scale (Never: “0”, Rarely: “1”, Sometimes: “2”, Frequently: “3”, and Always: “4”). The total score on the scale varies between 0-60, and as the score increases, the level of digital dementia also increases. The Cronbach α Reliability Coefficient of the scale was calculated as .92, indicating high reliability.</p> Conclusion <p>The “Digital Dementia Scale Adult Form” is valid in terms of scope and content and has high reliability.</p>