This paper describes a software package, named sigTOOL, for processing biological signals. The package runs in the MATLAB programming environment and has been designed to promote the sharing of laboratory-developed software across the worldwide web. As proof-of-concept of the design of the system, sigTOOL has been used to build an analysis application for dealing with neuroscience data complete with a user-friendly graphical user interface which implements a range of waveform and spike-train analysis functions. The interface allows many commonly used neuroscience data file formats to be loaded (including those of Alpha Omega, Cambridge Electronic Design, Cyberkinetics Inc., Molecular Devices, Nex Technologies and Plexon Instruments). Waveform analysis functions selectable from the interface support waveform averaging (mean and median), auto- and cross-correlation, power spectral analysis, coherence estimation, digital filtering (feedback and feedforward) and resampling. Spike-train analyses include interspike interval distributions, Poincaré plots, event auto- and cross-correlations, spike-triggered averaging, stimulus driven and phase-related peri-event time histograms and rasters as well as frequencygrams. User-developed additions to sigTOOL that are archived and distributed electronically will be added to the sigTOOL interface on-the-fly, without the need to modify the core sigTOOL code. Full sigTOOL functionality will be provided to support the user-developed code, including the ability to record a user action history for batch processing of files and support for exporting the results of analyses to external graphics editing software and spreadsheet-based data processing packages.