ofcourse
by defaullt oracle does that.
ignore=y is to say oracle to ignore the error message if the same object is already found
imp user/paswrd fromuser=scott touser=magellan ignore=y

bash-2.03$
bash-2.03$ exp mag/mag tables=l1

Export: Release 9.2.0.1.0 - Production on Thu Dec 18 12:16:22 2003

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

Connected to: Oracle9i Enterprise Edition Release 9.2.0.1.0 - 64bit Production
With the Partitioning and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production
Export done in US7ASCII character set and AL16UTF16 NCHAR character set
server uses WE8ISO8859P1 character set (possible charset conversion)

About to export specified tables via Conventional Path ...
. . exporting table                             L1          3 rows exported
Export terminated successfully without warnings.

----------------------------------------------------------------------

bash-2.03$ imp mag/mag file=expdat.dmp fromuser=mag touser=mag ignore=y

Import: Release 9.2.0.1.0 - Production on Thu Dec 18 12:17:06 2003

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

Connected to: Oracle9i Enterprise Edition Release 9.2.0.1.0 - 64bit Production
With the Partitioning and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production

Export file created by EXPORT:V09.02.00 via conventional path
import done in US7ASCII character set and AL16UTF16 NCHAR character set
import server uses WE8ISO8859P1 character set (possible charset conversion)
. . importing table                           "L1"          3 rows imported
Import terminated successfully without warnings.
bash-2.03$ sqlplus mag/mag

SQL*Plus: Release 9.2.0.1.0 - Production on Thu Dec 18 12:17:18 2003

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.

Connected to:
Oracle9i Enterprise Edition Release 9.2.0.1.0 - 64bit Production
With the Partitioning and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production

mag@mutation_mutation > select * from l1;

    DEPTNO DNAME
---------- ---------------------------------------------------------------------
-----------
        20 RESEARCH
        30 SALES
        40 OPERATIONS
        20 RESEARCH
        30 SALES
        40 OPERATIONS

6 rows selected.