Organizational climate and related factors are associated with outcome and are as such of vital interest for healthcare organizations. Organizational Readiness for Change (ORC) is the questionnaire used in the present study to assess the influence of organizational factors on implementation success. The respondents were employed in one of 203 Swedish municipalities within social work and psychiatric substance/abuse treatment services. They took part in a nationwide implementation project organized by the Swedish Association of Local Authorities and Regions (SALAR), commissioned by the Swedish National Board of Health and Welfare. Aim The aims were: (a) to identify classes (clusters) of employees with different ORC profiles on the basis of data collected in 2011 and (b) to investigate ORC profiles which predicted the use of assessment instruments, therapy methods and collaborative activities in 2011 and 2013. Design and recruitment The evaluation study applied a naturalistic design with registration of outcome at consecutive assessments. The participants were contacted via official e-mail addresses in their respective healthcare units and were encouraged by their officials to participate on a voluntary basis. Statistics Descriptive statistics were obtained using SPSS version 23. A latent profile analysis (LPA) using Mplus 7.3 was performed with a robust maximum likelihood estimator (MLR) to identify subgroups (clusters) based on the 18 ORC indexes. Results A total of 2402 employees responded to the survey, of whom 1794 (74.7%) completed the ORC scores. Descriptive analysis indicated that the respondents were a homogenous group of employees, where women (72.0%) formed the majority. Cronbach's alpha for the 18 ORC indexes ranged from α = 0.67 to α = 0.78. A principal component analysis yielded a four-factor solution explaining 62% of the variance in total ORC scores. The factors were: motivational readiness (α = 0.64), institutional resources (α = 0.52), staff attributes (α = 0.76), and organizational climate (α = 0.74). An LPA analysis of the four factors with their three distinct profiles provided the best data fit: Profile 3 (n = 614), Profile 2 (n = 934), and Profile 1 (n = 246). Respondents with the most favorable ORC scores (Profile 3) used significantly more instruments and more treatment methods and had a better collaborating network in 2011 as well as in 2013 compared to members in Profile 1, the least successful profile. Conclusion In a large sample of social work and healthcare professionals, ORC scores reflecting higher institutional resources, staff attributes and organizational climate and lower motivational readiness for change were associated with a successful implementation of good practice guidelines for the care and treatment of substance users in Sweden. Low motivational readiness as a construct may indicate satisfaction with the present situation. As ORC proved to be an indicator of successful dissemination of evidence-based guidelines into routine and specialist healthcare, it can be used to tailor interventions to individual employees or services and to improve the dissemination of and compliance with guidelines for the treatment of substance users. © 2017