diff --git a/wiretap/pcap-common.c b/wiretap/pcap-common.c
index e7e367f343..5185498648 100644
--- a/wiretap/pcap-common.c
+++ b/wiretap/pcap-common.c
@@ -1437,6 +1437,15 @@ pcap_read_erf_pseudoheader(FILE_T fh, wtap_rec *rec,
 			rec->ts.nsecs -= 1000000000;
 			rec->ts.secs += 1;
 		}
+
+		/*
+		 * This time stamp came from the ERF header, not from the
+		 * pcap packet header or pcapng block header, so its
+		 * precision is that of ERF time stamps, not the pcap
+		 * file's time stamp or the pcapng interface's time
+		 * stamp.
+		 */
+		rec->tsprec = WTAP_TSPREC_NSEC;
 	}
 
 	/*