diff --git a/cmd/mothd/httpd.go b/cmd/mothd/httpd.go
index 54ca156..1963f63 100644
--- a/cmd/mothd/httpd.go
+++ b/cmd/mothd/httpd.go
@@ -125,6 +125,22 @@ func (h *HTTPServer) RegisterHandler(mh MothRequestHandler, w http.ResponseWrite
 	}
 }
 
+// AssignParticipantHandler handles attempts to associate a participant with a team
+func (h *HTTPServer) AssignParticipantHandler(mh MothRequestHandler, w http.ResponseWriter, req *http.Request) {
+	if mh.participantID == "" {
+		jsend.Sendf(w, jsend.Fail, "empty name", "Participant ID may not be empty")
+		return
+	}
+
+	if err := mh.AssignParticipant(); err != ErrAlreadyRegistered {
+		jsend.Sendf(w, jsend.Success, "already assigned", "participant and team have already been associated")
+	} else if err != nil {
+		jsend.Sendf(w, jsend.Fail, "unable to associate participant and team", err.Error())
+	} else {
+		jsend.Sendf(w, jsend.Success, "assigned", "participant and team have been associated")
+	}
+}
+
 // AnswerHandler checks answer correctness and awards points
 func (h *HTTPServer) AnswerHandler(mh MothRequestHandler, w http.ResponseWriter, req *http.Request) {
 	cat := req.FormValue("cat")
diff --git a/cmd/mothd/server.go b/cmd/mothd/server.go
index 608e6d6..11f66c0 100644
--- a/cmd/mothd/server.go
+++ b/cmd/mothd/server.go
@@ -57,6 +57,7 @@ type StateProvider interface {
 	PointsLog() award.List
 	TeamName(teamID string) (string, error)
 	SetTeamName(teamID, teamName string) error
+	AssignParticipant(participantID string, teamID string) error
 	AwardPoints(teamID string, cat string, points int) error
 	LogEvent(event, participantID, teamID, cat string, points int, extra ...string)
 	Maintainer
@@ -176,6 +177,20 @@ func (mh *MothRequestHandler) Register(teamName string) error {
 	return mh.State.SetTeamName(mh.teamID, teamName)
 }
 
+// AssignParticipant associates a participant with a team
+func (mh *MothRequestHandler) AssignParticipant() error {
+	if mh.participantID == "" {
+		return fmt.Errorf("empty participant ID")
+	}
+
+	if mh.teamID == "" {
+		return fmt.Errorf("empty participant ID")
+	}
+
+	mh.State.LogEvent("assign", mh.participantID, mh.teamID, "", 0)
+	return mh.State.AssignParticipant(mh.participantID, mh.teamID)
+}
+
 // ExportState anonymizes team IDs and returns StateExport.
 // If a teamID has been specified for this MothRequestHandler,
 // the anonymized team name for this teamID has the special value "self".
diff --git a/cmd/mothd/state.go b/cmd/mothd/state.go
index 9d11621..037d82a 100644
--- a/cmd/mothd/state.go
+++ b/cmd/mothd/state.go
@@ -46,6 +46,7 @@ type State struct {
 
 	// Caches, so we're not hammering NFS with metadata operations
 	teamNames map[string]string
+	participantTeams map[string]string
 	pointsLog award.List
 	messages  string
 	lock      sync.RWMutex
@@ -60,6 +61,7 @@ func NewState(fs afero.Fs) *State {
 		eventStream: make(chan []string, 80),
 
 		teamNames: make(map[string]string),
+		participantTeams: make(map[string]string),
 	}
 	if err := s.reopenEventLog(); err != nil {
 		log.Fatal(err)
@@ -175,6 +177,48 @@ func (s *State) SetTeamName(teamID, teamName string) error {
 	return nil
 }
 
+// AssignParticipant associated a participant with a team
+// A participant can only be associated with one team at a time
+func (s *State) AssignParticipant(participantID string, teamID string) error {
+	idsFile, err := s.Open("participantids.txt")
+	if err != nil {
+		return fmt.Errorf("participant IDs file does not exist")
+	}
+	defer idsFile.Close()
+	found := false
+	scanner := bufio.NewScanner(idsFile)
+	for scanner.Scan() {
+		if scanner.Text() == participantID {
+			found = true
+			break
+		}
+	}
+	if !found {
+		return fmt.Errorf("participant ID not found in list of valid participant IDs")
+	}
+
+	_, err = s.TeamName(teamID)
+
+	if (err != nil) {
+		return fmt.Errorf("Provided team does not exist, or is not registered")
+	}
+
+	teamParticipantFilename := filepath.Join("participants", participantID)
+	teamParticipantFile, err := s.Fs.OpenFile(teamParticipantFilename, os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0644)
+	if os.IsExist(err) {
+		return ErrAlreadyRegistered
+	} else if err != nil {
+		return err
+	}
+	defer teamParticipantFile.Close()
+	log.Printf("Adding participant [%s] to team [%s]", participantID, teamID)
+	fmt.Fprintln(teamParticipantFile, teamID)
+
+	s.refreshNow <- true
+
+	return nil
+}
+
 // PointsLog retrieves the current points log.
 func (s *State) PointsLog() award.List {
 	s.lock.RLock()
@@ -308,6 +352,7 @@ func (s *State) maybeInitialize() {
 	s.RemoveAll("points.tmp")
 	s.RemoveAll("points.new")
 	s.RemoveAll("teams")
+	s.RemoveAll("participants")
 
 	// Open log file
 	if err := s.reopenEventLog(); err != nil {
@@ -319,6 +364,7 @@ func (s *State) maybeInitialize() {
 	s.Mkdir("points.tmp", 0755)
 	s.Mkdir("points.new", 0755)
 	s.Mkdir("teams", 0755)
+	s.Mkdir("participants", 0755)
 
 	// Preseed available team ids if file doesn't exist
 	if f, err := s.OpenFile("teamids.txt", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644); err == nil {
@@ -333,6 +379,19 @@ func (s *State) maybeInitialize() {
 		f.Close()
 	}
 
+	// Preseed available participants if file doesn't exist
+	if f, err := s.OpenFile("participantids.txt", os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644); err == nil {
+		id := make([]byte, 16)
+		for i := 0; i < 100; i++ {
+			for i := range id {
+				char := rand.Intn(len(DistinguishableChars))
+				id[i] = DistinguishableChars[char]
+			}
+			fmt.Fprintln(f, string(id))
+		}
+		f.Close()
+	}
+
 	// Create some files
 	if f, err := s.Create("initialized"); err == nil {
 		fmt.Fprintln(f, "initialized: remove to re-initialize the contest.")
@@ -451,6 +510,28 @@ func (s *State) updateCaches() {
 
 	}
 
+	{
+		// Update participant records
+		for k := range s.participantTeams {
+			delete(s.participantTeams, k)
+		}
+
+		participantsFs := afero.NewBasePathFs(s.Fs, "participants")
+		if dirents, err := afero.ReadDir(participantsFs, "."); err != nil {
+			log.Printf("Reading participant ids: %v", err)
+		} else {
+			for _, dirent := range dirents {
+				participantID := dirent.Name()
+				if participantTeamBytes, err := afero.ReadFile(participantsFs, participantID); err != nil {
+					log.Printf("Reading participant %s: %v", participantID, err)
+				} else {
+					teamID := strings.TrimSpace(string(participantTeamBytes))
+					s.participantTeams[participantID] = teamID
+				}
+			}
+		}
+	}
+
 	if bMessages, err := afero.ReadFile(s, "messages.html"); err == nil {
 		s.messages = string(bMessages)
 	}