diff --git a/doc/src/cursor.rst b/doc/src/cursor.rst
index 3982d94a..d5cf5244 100644
--- a/doc/src/cursor.rst
+++ b/doc/src/cursor.rst
@@ -444,20 +444,23 @@ The ``cursor`` class
         The :sql:`COPY` command is a PostgreSQL extension to the SQL standard.
         As such, its support is a Psycopg extension to the |DBAPI|.
 
-    .. method:: copy_from(file, table, sep='\\t', null='\\N', columns=None)
- 
+    .. method:: copy_from(file, table, sep='\\t', null='\\N', size=8192, columns=None)
+
         Read data *from* the file-like object *file* appending them to
-        the table named *table*.  *file* must have both
-        `!read()` and `!readline()` method.  See :ref:`copy` for an
-        overview.
+        the table named *table*.  See :ref:`copy` for an overview.
 
-        The optional argument *sep* is the columns separator and
-        *null* represents :sql:`NULL` values in the file.
+        :param file: file-like object to read data from.  It must have both
+            `!read()` and `!readline()` methods.
+        :param table: name of the table to copy data into.
+        :param sep: columns separator expected in the file. Defaults to a tab.
+        :param null: textual representation of :sql:`NULL` in the file.
+        :param size: size of the buffer used to read from the file.
+        :param columns: iterable with name of the columns to import.
+            The length and types should match the content of the file to read.
+            If not specified, it is assumed that the entire table matches the
+            file structure.
 
-        The *columns* argument is a sequence containing the name of the
-        fields where the read data will be entered.  Its length and column
-        type should match the content of the read file.  If not specifies, it
-        is assumed that the entire table matches the file structure.
+        Example::
 
             >>> f = StringIO("42\tfoo\n74\tbar\n")
             >>> cur.copy_from(f, 'test', columns=('num', 'data'))
@@ -476,14 +479,17 @@ The ``cursor`` class
     .. method:: copy_to(file, table, sep='\\t', null='\\N', columns=None)
 
         Write the content of the table named *table* *to* the file-like
-        object *file*.  *file* must have a `!write()` method.
-        See :ref:`copy` for an overview.
+        object *file*.  See :ref:`copy` for an overview.
 
-        The optional argument *sep* is the columns separator and
-        *null* represents :sql:`NULL` values in the file.
+        :param file: file-like object to write data into.  It must have a
+            `!write()` method.
+        :param table: name of the table to copy data from.
+        :param sep: columns separator expected in the file. Defaults to a tab.
+        :param null: textual representation of :sql:`NULL` in the file.
+        :param columns: iterable with name of the columns to export.
+            If not specified, export all the columns.
 
-        The *columns* argument is a sequence of field names: if not
-        `!None` only the specified fields will be included in the dump.
+        Example::
 
             >>> cur.copy_to(sys.stdout, 'test', sep="|")
             1|100|abc'def
@@ -499,17 +505,18 @@ The ``cursor`` class
             from the backend.
 
 
-    .. method:: copy_expert(sql, file [, size])
+    .. method:: copy_expert(sql, file, size=8192)
 
         Submit a user-composed :sql:`COPY` statement. The method is useful to
         handle all the parameters that PostgreSQL makes available (see
         |COPY|__ command documentation).
 
-        *file* must be an open, readable file for :sql:`COPY FROM` or an
-        open, writeable file for :sql:`COPY TO`. The optional *size*
-        argument, when specified for a :sql:`COPY FROM` statement, will be
-        passed to *file*\ 's read method to control the read buffer
-        size.
+        :param sql: the :sql:`COPY` statement to execute.
+        :param file: a file-like object; must be a readable file for
+            :sql:`COPY FROM` or an writeable file for :sql:`COPY TO`.
+        :param size: size of the read buffer to be used in :sql:`COPY FROM`.
+
+        Example:
 
             >>> cur.copy_expert("COPY test TO STDOUT WITH CSV HEADER", sys.stdout)
             id,num,data
diff --git a/psycopg/cursor_type.c b/psycopg/cursor_type.c
index 048ab6d8..717cf9cc 100644
--- a/psycopg/cursor_type.c
+++ b/psycopg/cursor_type.c
@@ -1213,7 +1213,7 @@ static int _psyco_curs_copy_columns(PyObject *columns, char *columnlist)
 /* extension: copy_from - implements COPY FROM */
 
 #define psyco_curs_copy_from_doc \
-"copy_from(file, table, sep='\\t', null='\\N', columns=None) -- Copy table from file."
+"copy_from(file, table, sep='\\t', null='\\N', size=8192, columns=None) -- Copy table from file."
 
 static int
 _psyco_curs_has_read_check(PyObject* o, void* var)
@@ -1454,7 +1454,7 @@ exit:
 */
 
 #define psyco_curs_copy_expert_doc \
-"copy_expert(sql, file, size=None) -- Submit a user-composed COPY statement.\n" \
+"copy_expert(sql, file, size=8192) -- Submit a user-composed COPY statement.\n" \
 "`file` must be an open, readable file for COPY FROM or an open, writeable\n"   \
 "file for COPY TO. The optional `size` argument, when specified for a COPY\n"   \
 "FROM statement, will be passed to file's read method to control the read\n"    \