This paper considers an adaptive observer construction for summational type state space (StSS) equation, which is a suitable mathematical expression for modeling physical dynamical systems with parasitic elements. Although this expression is appropriate to the realities of physical and engineering problems in terms of the system identification and the control system design, to our knowledge, little is known about the StSS identification methods except the MOESP based method. So, we propose a StSS adaptive observer method, which is based on Kreisselmeier adaptive observer.