The importance of organizational issues to assess the success of international development project has not been fully considered yet. An analysis of the literature on the project success definition, focused on the success criteria and success factors, was carried out by surveying the contribution of different authors and approaches. Traditionally projects were perceived as successful when they met time, budget and performance goals, assuming a basic similarity among projects (universalistic approach). However, starting from a non‐universalistic approach, the importance of organization’s effectiveness, in terms of relations sustainability, emerged as a dimension able to define and assess a project success (Belassi W., Tukel O.I., 1996). Based on previous research contributions on the factors influencing the relations between organizations (Zanasi C., Rota C., 2009), the paper expands the analysis of the influence of human resource management on organizational climate that, in turn, influences the relation sustainability between project manager and project team involved in international cooperation for development. A detailed analysis of these relations is provided and a research hypothesis are built. A questionnaire on previous contributions was adapted to collect data for a Structural Equation Modelling (SEM) analysis. Five dimensions of organizational climate (Zeitz G. et al., 1997) (trust, communication, innovation, job challenge, social cohesion), four dimensions of human resource management (Snell S.A., Dean J.W, 1992) (staff recruitment, training, performance appraisal, reward system) and two dimension for sustainable relations (Fisher C., Reynolds N., 2008) (relations quality and strength) are reported and measured by using a 5 point Likert scale. The sample size is still in progress. The first results on internal consistency reliability coefficients (Cronbach’s alpha) are satisfactory.