diff --git a/phosphor-regulators/src/pmbus_error.hpp b/phosphor-regulators/src/pmbus_error.hpp
new file mode 100644
index 0000000..b589526
--- /dev/null
+++ b/phosphor-regulators/src/pmbus_error.hpp
@@ -0,0 +1,68 @@
+/**
+ * Copyright © 2020 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include <exception>
+#include <string>
+
+namespace phosphor::power::regulators
+{
+
+/**
+ * @class PMBusError
+ *
+ * An error that occurred while sending PMBus commands or converting data
+ * between PMBus formats.
+ */
+class PMBusError : public std::exception
+{
+  public:
+    // Specify which compiler-generated methods we want
+    PMBusError() = delete;
+    PMBusError(const PMBusError&) = default;
+    PMBusError(PMBusError&&) = default;
+    PMBusError& operator=(const PMBusError&) = default;
+    PMBusError& operator=(PMBusError&&) = default;
+    virtual ~PMBusError() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param error error message
+     */
+    explicit PMBusError(const std::string& error) :
+        error{"PMBusError: " + error}
+    {
+    }
+
+    /**
+     * Returns the description of this error.
+     *
+     * @return error description
+     */
+    const char* what() const noexcept override
+    {
+        return error.c_str();
+    }
+
+  private:
+    /**
+     * Error message.
+     */
+    const std::string error{};
+};
+
+} // namespace phosphor::power::regulators