diff --git a/lib/libsys/kqueue.2 b/lib/libsys/kqueue.2
--- a/lib/libsys/kqueue.2
+++ b/lib/libsys/kqueue.2
@@ -592,6 +592,40 @@
 The process has exited.
 The exit status will be stored in
 .Va data .
+.It Dv NOTE_FORK
+The process has forked.
+The process identifier of the most recently forked child
+is returned in the
+.Va data
+field.
+.Pp
+The identifier is advisory;
+if several children were spawned before the event is returned,
+only one of the PIDs is returned.
+Other means might provide the reliable reporting of the children.
+For instance, debugging the process with subscription for relevant
+events would serialize forks.
+See
+.Xr ptrace 2
+and the description of the
+.Dv PT_FOLLOW_FORK
+request.
+.Pp
+Unlike the
+.Dv EVFILT_PROC
+filter,
+the
+.Dv NOTE_TRACK
+pseudo-event is not supported.
+.Pp
+If both
+.Dv NOTE_EXIT
+and
+.Dv NOTE_FORK
+events are reported, then the
+.Va data
+field contains the exit status of the process,
+the last child's PID is not returned.
 .It Dv NOTE_PDSIGCHLD
 Activates on events that are reported through
 .Xr pdwait 2
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -781,6 +781,7 @@
 	 * Tell any interested parties about the new process.
 	 */
 	knote_fork(p1->p_klist, p2->p_pid);
+	procdesc_fork(p1, p2->p_pid);
 
 	PROC_UNLOCK(p1);
 	SDT_PROBE3(proc, , , create, p2, p1, fr->fr_flags);
diff --git a/sys/kern/sys_procdesc.c b/sys/kern/sys_procdesc.c
--- a/sys/kern/sys_procdesc.c
+++ b/sys/kern/sys_procdesc.c
@@ -335,6 +335,22 @@
 	wakeup(&p->p_procdesc);
 }
 
+void
+procdesc_fork(struct proc *p, pid_t child_pid)
+{
+	struct procdesc *pd;
+
+	PROC_LOCK_ASSERT(p, MA_OWNED);
+	pd = p->p_procdesc;
+	if (pd == NULL)
+		return;
+
+	PROCDESC_LOCK(pd);
+	pd->pd_last_child = child_pid;
+	KNOTE_LOCKED(&pd->pd_selinfo.si_note, NOTE_FORK);
+	PROCDESC_UNLOCK(pd);
+}
+
 /*
  * When a process descriptor is reaped, perhaps as a result of close(), release
  * the process's reference on the process descriptor.
@@ -506,6 +522,9 @@
 		return (1);
 	}
 
+	if ((kn->kn_fflags & NOTE_FORK) != 0)
+		kn->kn_data = pd->pd_last_child;
+
 	return (kn->kn_fflags != 0);
 }
 
diff --git a/sys/sys/event.h b/sys/sys/event.h
--- a/sys/sys/event.h
+++ b/sys/sys/event.h
@@ -204,7 +204,8 @@
  */
 #define	NOTE_EXIT	0x80000000		/* proc/procdesc: process
 						   exited */
-#define	NOTE_FORK	0x40000000		/* proc: process forked */
+#define	NOTE_FORK	0x40000000		/* proc/procdesc: process
+						   forked */
 #define	NOTE_EXEC	0x20000000		/* proc: process exec'd */
 #define	NOTE_PDSIGCHLD	0x10000000		/* procdesc: pdwait() info
 						   available */
diff --git a/sys/sys/procdesc.h b/sys/sys/procdesc.h
--- a/sys/sys/procdesc.h
+++ b/sys/sys/procdesc.h
@@ -64,6 +64,7 @@
 	 */
 	struct proc	*pd_proc;		/* (t) Process. */
 	pid_t		 pd_pid;		/* (c) Cached pid. */
+	pid_t		 pd_last_child;		/* (p) Pid of the last child. */
 	u_int		 pd_refcount;		/* (r) Reference count. */
 	u_int		 pd_fpcount;		/* (p|t) files referencing me */
 
@@ -102,6 +103,7 @@
  * In-kernel interfaces to process descriptors.
  */
 bool	 procdesc_exit(struct proc *);
+void	 procdesc_fork(struct proc *p, pid_t child_pid);
 void	 procdesc_jobstate(struct proc *p);
 int	 kern_pdgetpid(struct thread *, int fd, const cap_rights_t *,
 	    pid_t *pidp);