diff --git a/internal/domains/sensors/repository.go b/internal/domains/sensors/repository.go
index 1b746ba..4f64d28 100644
--- a/internal/domains/sensors/repository.go
+++ b/internal/domains/sensors/repository.go
@@ -6,7 +6,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/jackc/pgx/v5/pgtype"
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
@@ -67,19 +66,28 @@ func (p *pgxRepo) ReadSensor(sensorID string) (Sensor, error) {
 	return s, nil
 }
 
-const readSensorValuesBySensorID = ``
+const readSensorValuesBySensorID = `select sensor_id, value, created_at from registry where sensor_id = $1 and created_at >= $2 and created_at <= $3 order by created_at desc`
 
 func (p *pgxRepo) ReadSensorValues(sensorID string, from, to time.Time) ([]SensorData, error) {
-	fromPgType := pgtype.Timestamp{
-		Time:  from,
-		Valid: true,
+	rows, err := p.Query(context.Background(), readSensorValuesBySensorID, sensorID, from, to)
+	if err != nil {
+		return nil, err
 	}
-	toPgType := pgtype.Timestamp{
-		Time:  to,
-		Valid: true,
+	defer rows.Close()
+
+	data := []SensorData{}
+	for rows.Next() {
+		var sd SensorData
+		if err := rows.Scan(&sd.SensorID, &sd.Value, &sd.Timestamp); err != nil {
+			return nil, err
+		}
+		data = append(data, sd)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
 	}
 
-	panic("unimplemented")
+	return data, nil
 }
 
 const readAllSensorsQuery = `select sensor_id, sensor_type, sampling_interval, threshold_above, threshold_below from sensors order by created_at desc`
@@ -196,9 +204,29 @@ func (i *inMemory) ReadSensor(sensorID string) (Sensor, error) {
 }
 
 func (i *inMemory) ReadSensorValues(sensorID string, from time.Time, to time.Time) ([]SensorData, error) {
-	// holds only last 100 values for every sensor
+	i.mu.Lock()
+	defer i.mu.Unlock()
 
-	panic("unimplemented")
+	sensor, exists := i.sensors[sensorID]
+	if !exists {
+		return nil, ErrSensorNotFound
+	}
+
+	if sensor.SensorData == nil {
+		return []SensorData{}, nil
+	}
+
+	data := []SensorData{}
+	fromUnix := from.Unix()
+	toUnix := to.Unix()
+
+	for timestamp, sd := range *sensor.SensorData {
+		if int64(timestamp) >= fromUnix && int64(timestamp) <= toUnix {
+			data = append(data, sd)
+		}
+	}
+
+	return data, nil
 }
 
 func (i *inMemory) ReadAllSensors() ([]Sensor, error) {
@@ -275,11 +303,22 @@ func (d *DecoratorRepo) ReadSensor(sensorID string) (Sensor, error) {
 
 func (d *DecoratorRepo) ReadSensorValues(sensorID string, from, to time.Time) ([]SensorData, error) {
 	values, err := d.memory.ReadSensorValues(sensorID, from, to)
-	if err == nil && len(values) > 0 {
-		return values, nil
+	if err != nil || len(values) == 0 {
+		return d.db.ReadSensorValues(sensorID, from, to)
 	}
 
-	return d.db.ReadSensorValues(sensorID, from, to)
+	var oldestTimestamp *time.Time
+	for _, v := range values {
+		if oldestTimestamp == nil || v.Timestamp.Before(*oldestTimestamp) {
+			oldestTimestamp = v.Timestamp
+		}
+	}
+
+	if oldestTimestamp != nil && oldestTimestamp.After(from) {
+		return d.db.ReadSensorValues(sensorID, from, to)
+	}
+
+	return values, nil
 }
 
 func (d *DecoratorRepo) ReadAllSensors() ([]Sensor, error) {