diff --git a/drivers/pcf857x/pcf857x_saul.c b/drivers/pcf857x/pcf857x_saul.c
new file mode 100644
index 0000000000..84edc7f2a9
--- /dev/null
+++ b/drivers/pcf857x/pcf857x_saul.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2018 Gunar Schorcht
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     drivers_pcf857x
+ * @brief       PCF857X adaption to the RIOT actuator/sensor interface
+ * @author      Gunar Schorcht <gunar@schorcht.net>
+ * @file
+ */
+#if MODULE_SAUL_GPIO
+
+#include <string.h>
+
+#include "saul.h"
+#include "pcf857x.h"
+
+extern pcf857x_t pcf857x_devs[];
+
+static int read(const void *dev, phydat_t *res)
+{
+    const pcf857x_saul_gpio_params_t *p = (const pcf857x_saul_gpio_params_t *)dev;
+    int inverted = (p->gpio.flags & SAUL_GPIO_INVERTED);
+
+    res->val[0] = (pcf857x_gpio_read(&pcf857x_devs[p->dev],
+                                     p->gpio.pin)) ? !inverted : inverted;
+    res->unit = UNIT_BOOL;
+    res->scale = 0;
+    return 1;
+}
+
+static int write(const void *dev, phydat_t *state)
+{
+    const pcf857x_saul_gpio_params_t *p = (const pcf857x_saul_gpio_params_t *)dev;
+    int inverted = (p->gpio.flags & SAUL_GPIO_INVERTED);
+    int value = (state->val[0] ? !inverted : inverted);
+
+    pcf857x_gpio_write(&pcf857x_devs[p->dev], p->gpio.pin, value);
+    return 1;
+}
+
+const saul_driver_t pcf857x_gpio_out_saul_driver = {
+    .read = read,
+    .write = write,
+    .type = SAUL_ACT_SWITCH
+};
+
+const saul_driver_t pcf857x_gpio_in_saul_driver = {
+    .read = read,
+    .write = saul_notsup,
+    .type = SAUL_SENSE_BTN
+};
+#endif /* MODULE_SAUL_GPIO */
diff --git a/drivers/saul/init_devs/auto_init_pcf857x.c b/drivers/saul/init_devs/auto_init_pcf857x.c
new file mode 100644
index 0000000000..9044e8fdd9
--- /dev/null
+++ b/drivers/saul/init_devs/auto_init_pcf857x.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2018 Gunar Schorcht
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     drivers_pcf857x
+ * @ingroup     sys_auto_init_saul
+ * @brief       Auto initialization of Texas Instruments PCF857X I2C I/O expanders
+ * @author      Gunar Schorcht <gunar@schorcht.net>
+ * @file
+ * @{
+ */
+
+#if MODULE_PCF857X && MODULE_SAUL_GPIO
+
+#include "assert.h"
+#include "log.h"
+
+#include "saul_reg.h"
+#include "saul/periph.h"
+
+#include "pcf857x.h"
+#include "pcf857x_params.h"
+
+/**
+ * @brief   Number of configured PCF857X I/O expander devices
+ */
+#define PCF857X_NUM             ARRAY_SIZE(pcf857x_params)
+
+/**
+ * @brief   Number of configured SAUL PCF857X I/O pins
+ */
+#define PCF857X_SAUL_GPIO_NUMOF ARRAY_SIZE(pcf857x_saul_gpio_params)
+
+/**
+ * @brief   Number of saul info
+ */
+#define PCF857X_INFO_NUM        ARRAY_SIZE(pcf857x_saul_info)
+
+/**
+ * @brief   Allocate the memory for the PCF857X I/O expander device descriptors
+ */
+pcf857x_t pcf857x_devs[PCF857X_NUM];
+
+/**
+ * @brief   Allocate the memory for PCF857X I/O expander SAUL registry entries
+ */
+static saul_reg_t pcf857x_saul_reg_entries[PCF857X_SAUL_GPIO_NUMOF];
+
+/**
+ * @brief   Reference the PCF857X I/O expander input mode driver struct
+ */
+extern saul_driver_t pcf857x_gpio_in_saul_driver;
+
+/**
+ * @brief   Reference to the PCF857X I/O expander output mode driver struct
+ */
+extern saul_driver_t pcf857x_gpio_out_saul_driver;
+
+void auto_init_pcf857x(void)
+{
+    for (unsigned int i = 0; i < PCF857X_NUM; i++) {
+        LOG_DEBUG("[auto_init_saul] initializing PCF857X I/O expander dev #%u\n", i);
+        pcf857x_init(&pcf857x_devs[i], &pcf857x_params[i]);
+    }
+
+    for (unsigned int i = 0; i < PCF857X_SAUL_GPIO_NUMOF; i++) {
+        const pcf857x_saul_gpio_params_t *p = &pcf857x_saul_gpio_params[i];
+
+        LOG_DEBUG("[auto_init_saul] initializing PCF857X GPIO #%u\n", i);
+
+        /* check the PCF857X device index */
+        assert(p->dev < PCF857X_NUM);
+        /* check the PCF857X device index */
+        assert(p->gpio.pin < PCF857X_GPIO_PIN_NUM);
+
+        pcf857x_saul_reg_entries[i].dev = (void *)p;
+        pcf857x_saul_reg_entries[i].name = p->gpio.name;
+        if ((p->gpio.mode == GPIO_IN) ||
+            (p->gpio.mode == GPIO_IN_PD) ||
+            (p->gpio.mode == GPIO_IN_PU)) {
+            pcf857x_saul_reg_entries[i].driver = &pcf857x_gpio_in_saul_driver;
+        }
+        else {
+            pcf857x_saul_reg_entries[i].driver = &pcf857x_gpio_out_saul_driver;
+        }
+        /* initialize the PCF857X pin */
+        pcf857x_gpio_init(&pcf857x_devs[p->dev], p->gpio.pin, p->gpio.mode);
+        /* set initial pin PCF857X state if configured */
+        if (p->gpio.flags & (SAUL_GPIO_INIT_CLEAR | SAUL_GPIO_INIT_SET)) {
+            phydat_t s;
+            s.val[0] = (p->gpio.flags & SAUL_GPIO_INIT_SET);
+            pcf857x_saul_reg_entries[i].driver->write(p, &s);
+        }
+        /* add to registry */
+        saul_reg_add(&(pcf857x_saul_reg_entries[i]));
+    }
+}
+#else
+typedef int dont_be_pedantic;
+#endif /* MODULE_PCF857X && MODULE_SAUL_GPIO */
diff --git a/drivers/saul/init_devs/init.c b/drivers/saul/init_devs/init.c
index ebacd494e8..e052c8410c 100644
--- a/drivers/saul/init_devs/init.c
+++ b/drivers/saul/init_devs/init.c
@@ -223,6 +223,10 @@ void saul_init_devs(void)
         extern void auto_init_pca9685(void);
         auto_init_pca9685();
     }
+    if (IS_USED(MODULE_PCF857X)) {
+        extern void auto_init_pcf857x(void);
+        auto_init_pcf857x();
+    }
     if (IS_USED(MODULE_PH_OEM)) {
         extern void auto_init_ph_oem(void);
         auto_init_ph_oem();