diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -53,7 +53,9 @@ qt5_wrap_ui(UI_FILES mainwindow.ui portc
 
 # Tell CMake to create the helloworld executable
 add_executable(serialplot WIN32 main.cpp mainwindow.cpp portcontrol.cpp
-  customcheckablebutton.cpp ${UI_FILES} misc/windows_icon.rc)
+  customcheckablebutton.cpp
+  zoomer.cpp
+  ${UI_FILES} misc/windows_icon.rc)
 
 # Use the Widgets module from Qt 5.
 target_link_libraries(serialplot ${QWT_LIBRARY})
diff --git a/mainwindow.cpp b/mainwindow.cpp
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -134,6 +134,10 @@ MainWindow::MainWindow(QWidget *parent) 
         curves[i]->attach(ui->plot);
     }
 
+    // init zoomer
+    zoomer = new Zoomer(ui->plot->canvas(), false);
+    zoomer->setZoomBase();
+
     // init number format
     if (numberFormatButtons.checkedId() >= 0)
     {
diff --git a/mainwindow.h b/mainwindow.h
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -33,6 +33,7 @@
 #include <QtGlobal>
 #include <qwt_plot_curve.h>
 #include <qwt_plot_textlabel.h>
+#include "zoomer.h"
 
 #include "portcontrol.h"
 #include "ui_about_dialog.h"
@@ -85,6 +86,8 @@ private:
     // `data` contains i th channels data
     void addChannelData(unsigned int channel, DataArray data);
 
+    Zoomer* zoomer;
+
     NumberFormat numberFormat;
     unsigned int sampleSize; // number of bytes in the selected number format
     double (MainWindow::*readSample)();
diff --git a/zoomer.cpp b/zoomer.cpp
new file mode 100644
--- /dev/null
+++ b/zoomer.cpp
@@ -0,0 +1,44 @@
+/*
+  Copyright © 2015 Hasan Yavuz Özderya
+
+  This file is part of serialplot.
+
+  serialplot is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  serialplot is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with serialplot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "zoomer.h"
+#include <qwt_plot.h>
+#include <QtDebug>
+
+Zoomer::Zoomer(QWidget* widget, bool doReplot) :
+    QwtPlotZoomer(widget, doReplot)
+{
+    // do nothing
+}
+
+void Zoomer::zoom(int up)
+{
+    if (up == +1)
+    {
+        this->setZoomBase(this->plot());
+    }
+
+    QwtPlotZoomer::zoom(up);
+
+    if (up == 0)
+    {
+        this->plot()->setAxisAutoScale(QwtPlot::yLeft);
+        this->plot()->replot();
+    }
+}
diff --git a/zoomer.h b/zoomer.h
new file mode 100644
--- /dev/null
+++ b/zoomer.h
@@ -0,0 +1,34 @@
+/*
+  Copyright © 2015 Hasan Yavuz Özderya
+
+  This file is part of serialplot.
+
+  serialplot is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  serialplot is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with serialplot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef ZOOMER_H
+#define ZOOMER_H
+
+#include <qwt_plot_zoomer.h>
+
+class Zoomer : public QwtPlotZoomer
+{
+    Q_OBJECT
+
+public:
+    Zoomer(QWidget *, bool doReplot=true);
+    void zoom(int up);
+};
+
+#endif // ZOOMER_H