Thanks Narasimhan for the question posed.
The answer depends upon so many factors: the size and structure of the organisation in question, its culture, whom you are directing the question to, etc.
The following website
HR Survey: Who Should HR report to? quotes a survey conducted in 2006. according to which of the 93 respondents
"Eight two (82) percent identified the CEO as the senior executive to whom HR should report. Eleven (11) percent suggested the COO and six (6) percent chose other. Zero (0) percent selected the CFO, which ironically oversees the HR function in many organizations."
Leadership and Management Success Tips: Business Management Success Tips - Why HR Should Never Report to Finance In this website the author gives the reason why HR should not report to Fiance, though that is what happens in a number of organisations.
One more site with the views of Dr. John Sullivan of San Francisco State University can be found at
<link no longer exists - removed>
Have a nice day.
Narasimhan