For the analysis of physiological signals, such as ECGs, continuous blood pressure recordings etc., access to the raw signal data as well as to processed data is mandatory. Up to now, there is no computer program which allows access to raw and processed data independently from the file formats used. Thus, programs have to be adapted to each new file format. The aim of the programming library 'libRASCH', is to provide an interface which allows the access to physiological signals in a consistent way. libRASCH is written in C and runs under Linux and Windows. The source code of libRASCH is published under the GNU LGPL. A plugin mechanism for extension of the library was implemented. Support for some widely used data formats (e.g. EDF(+), MIT/BIH) is already available. API bindings for several programming languages are available. On the libRASCH web-site www.librasch.org, the source code of libRASCH and further informations are available.