The Spanish government created in 1902 a research laboratory for Cajal, 1906 Nobel Prize and founder of modern neuroscience. The laboratory was translated, enlarged and renamed as Instituto Cajal in 1993 and incorporated to the CSIC in 1939. The excessive morphological specialization of the institute and the explosion of neuroscience as a multidisciplinary discipline were the conditions for a radical renovation initiated in 1985 under the auspices of the presidency of the CSIC and following the recommendations of several international advisory boards. The transformation of the Cajal Institute in a competitive multidisciplinary research centre culminated in 1989, with the inauguration of new facilities in its present location. As a result of the extreme success of this transformation the Cajal Institute has now grown to unpredicted dimensions of infrastructure and personnel that demand a new physical location to allow for its continuous growth as a leading European center in neuroscience research.