The purpose of this research was to determine and analyse diversity in various features of R&D projects implemented in the science sector in Poland, financed mostly from public funds. More exactly, the following aspects of R&D projects implemented in the science sector in Poland were examined: the relation between the actually achieved and the initially set goal, the project management methodologies and project time management methods used, features of the project team, the relation between the plan and the actual project realisation and management difficulties encountered in practice. These aspects and their diversity were examined in the context of the whole country, of various fields of science and various research units implementing pure research (the ‘R’ area) or applied research and experimental development (the ‘D’ area). The research was conducted by means of survey methodology covering a sample of participants of R&D projects in the science sector in Poland. The results were analysed by means of statistical methods (which constitutes a clear novelty with respect to the existing literature on R&D projects) and statistically significant phenomena gave rise to several important conclusions on how R&D projects implemented in the science sector are managed and what their realisation looks like in various fields of science and various institutions, in a relatively new EU members state and a former communist country like Poland. These conclusions may be the basis for important hypotheses (which require further research) on the project management quality in the science sector in Poland and in similar countries, which is closely linked to the problem of public money allocation, its efficient spending and control. Also, practical suggestions on improvement measures in the science sector with respect to R&D projects, limited not only to countries like Poland, but of a more general nature, are formulated.