We have built a microcomputer‐controlled x‐ray absorption spectrometer which is capable of measuring 100‐&mgr;s‐resolved extended x‐ray absorption fine structure (EXAFS) of dynamic systems. The spectrometer integrates the x‐ray absorption signals over a time interval &tgr; at any timetmeasured from the time of sample excitation. A series of absorption data of differenttis measured for a given x‐ray energy. The process is repeated for as many different x‐ray energies as required. The lower limit on &tgr; is determined by the concentration of sample and the intensity of synchrotron radiation. The system was recently tested at Stanford Synchrotron Radiation Laboratory using a carboxymyoglobin sample. We present the raw data here to demonstrate the feasibility of this spectrometer.