Exhibit 21.1 HRPT PROPERTIES TRUST SUBSIDIARIES OF THE REGISTRANT 1735 Market Street Properties Trust - (Maryland) Causeway Holdings, Inc. - (Massachusetts) Church Creek Corporation - (Massachusetts) EPA Golden, L.P. - (Delaware) Health and Retirement Properties International, Inc - (Delaware) Hub Acquisition Trust - (Maryland) Hub LA Limited Partnership (98%) - (Delaware) Hub LA Properties Trust - (Maryland) Hub Management, Inc. - (Delaware) Hub Properties Trust - (Maryland) Hub Realty Buffalo, Inc. - (Delaware) Hub Realty College Park I, LLC - (Maryland) Hub Realty College Park, Inc - (Delaware) Hub Realty Funding, Inc.- (Delaware) Hub Realty Golden, Inc. - (Delaware) Hub Realty Kansas City, Inc. - (Delaware) Hub Realty Richland, Inc - (Delaware) Hub RI Properties Trust - (Maryland) Hub Woodmont Investment Trust - (Maryland) Hub Woodmont Limited Liability Company - (Delaware) Indemnity Collection Corporation - (Delaware) Nine Penn Center Associates, L.P. - (Pennsylvania) Nine Penn Center Properties Trust - (Maryland) Research Park Properties Trust - (Maryland) Senior Housing Properties Trust - (Maryland) SPTBROOK Properties Trust - (Maryland) SPTIHS Properties Trust - (Maryland) SPTGEN Properties Trust - (Maryland) SPTMISC Properties Trust - (Maryland) SPTMNR Properties Trust - (Maryland) SPTMRT Properties Trust - (Maryland) SPTSUN Properties Trust - (Maryland)