Using panel data for all manufacturing firms in the German Federal State of Lower Saxony in this paper the age distribution of jobs existing in 1992 is analyzed. Four conclusions emerge: The porportion of long-lasting jobs amounts to about 75 percent in firms that were founded prior to 1978. Old jobs are relatively more frequently found in establishments that belong to a multi-establishment enterprise. Neither the sector nor the technological intensity do matter for the proportion of old jobs. Firm size is not related to the proportion of long lasting jobs.