The article begins with a review of the concepts regarding the interrelationships between knowledge and urban development, proposing a scheme of four main channels whereby cities join the knowledge society: namely, economic structure, human capital, innovation effort and networking. Upon this basis, Spanish cities are subjected to a comparative analysis of their knowledge indicators in each of these components, considering the degree of spatial concentration and possible spatial correlations among these indicators. The analysis concludes with a typology of Spanish cities according to ways of access to the knowledge society.