Thanks Sergey.

I found a shorter way:

create function dbo.ufn_getLastModifDate(@FileName varchar(250))
returns varchar(100) as 
begin
     declare @strDate varchar(100), @objFSO int, @objFile int
     exec sp_oacreate 'Scripting.FileSystemObject', @objFso out
     exec sp_oamethod @objFso, 'GetFile', @objFile out, @FileName
     exec sp_oagetproperty @objFile, 'DateLastModified', @strDate out
     exec sp_oadestroy @objFile
     exec sp_oadestroy @objFso
     return @strDate
end

select dbo.ufn_getLastModifDate('c:\temp\somefile.txt')

>>Is there a way to retreive the modified date of a file (that I know the name and the path) from a stored procedure ?
>
>You can use FileSystemObject
>

>IF EXISTS (SELECT * FROM   sysobjects
>	   WHERE  name = N'usp_FileDate')
>	DROP PROCEDURE usp_FileDate
>GO
>----------------------------------------------------
>CREATE PROCEDURE usp_FileDate (@FileName varchar(64), @FileDate datetime OUTPUT)
>AS
>BEGIN
>DECLARE @RetCode int, @FileSystem int, @FileHandle int
>DECLARE @YesNo int, @File int
>DECLARE @hr int, @source varchar(255), @description varchar(255)
>
>EXECUTE @RetCode = sp_OACreate 'Scripting.FileSystemObject', @FileSystem OUTPUT
>IF @@ERROR > 0 GOTO ErrorHandler
>-- Check if file exists
>EXECUTE @RetCode = sp_OAMethod @FileSystem, 'FileExists', @YesNo OUTPUT, @FileName
>IF @@ERROR > 0 GOTO ErrorHandler
>IF @RetCode > 0 BEGIN
>	EXEC @hr = sp_OAGetErrorInfo @FileSystem, @source OUT, @description OUT
>	GOTO DisplayError
>END
>
>IF @YesNo = 0
>        -- File doesn't exist
>	RETURN -1
>-- Get file object
>EXECUTE @RetCode = sp_OAMethod @FileSystem, 'GetFile', @File OUTPUT, @FileName
>IF @@ERROR > 0 GOTO ErrorHandler
>IF @RetCode > 0 BEGIN
>	EXEC @hr = sp_OAGetErrorInfo @FileSystem, @source OUT, @description OUT
>	GOTO DisplayError
>END
>-- Read 'DateLastModified' property of the file object
>EXECUTE @RetCode = sp_OAGetProperty @File, 'DateLastModified', @Filedate OUTPUT
>IF @@ERROR > 0 GOTO ErrorHandler
>IF @RetCode > 0 BEGIN
>	EXEC @hr = sp_OAGetErrorInfo @File, @source OUT, @description OUT
>	GOTO DisplayError
>END
>
>RETURN 0
>
>ErrorHandler:
>        RETURN -99
>
>DisplayError:
>	PRINT 'OLE Automation Error Information'
>	IF @hr = 0
>	BEGIN
>    	    PRINT '  Source: ' + @source
>	    PRINT '  Description: ' + @description		
>	END
>RETURN -99		
>
>END
>

>

>DECLARE @RetCode int, @dt datetime
>EXEC @RetCode = usp_FileDate 'C:\boot.ini', @dt OUTPUT
>SELECT @dt, @RetCode
>