PayPal used to avoid providing any list where PayPal is not supported.
The following list will show where PayPal is accepted.https://www.paypal.com/webapps/mpp/country-worldwide

But following are some which are unsupported to both send and receive payment using PayPal. Some country migh have support for either sending or receiving payment.
PayPal used to update countries send and receive status, which you can find using the following link 

https://www.paypal.com/cgi-bin/webscr?cmd=_display-country-functionality-outside 

Afghanistan,Cocos (Keeling) Islands,HaitiTromelin IslandAkrotiriCoral Sea IslandsHeard Island and McDonald Islands,Navassa IslandUzbekistanAmerican Samoa,Cote dIvoire,Iran,Nigeria,Virgin Islands,Antarctica,Cuba,Isle of Man,Northern Mariana Islands,Wake Island,Ashmore and Cartier Islands,Dhekelia, Jan Mayen,PakistanWest BankBangladeshEgypt, JerseyParacel IslandsWestern SaharaBassas da IndiaEquatorial GuineaJuan de Nova IslandParaguay Zimbabwe,Belarus,Europa IslandKorea NorthPuerto RicoBouvet Island,French Southern and Antarctic Lands,Lebanon,Serbia and Montenegro,British Indian Ocean Territory,Gaza Strip,Liberia,South Georgia and the South Sandwich Islands,Burma,Georgia,Libya,Spratly Islands,Cameroon,Ghana,Macau,Sudan,Central African Republic, Glorioso Islands, Macedonia, Syria, Christmas Island, Guam, Federated States of Micronesia,Timor-Leste, Clipperton Island, Guernsey, Moldova, Tokelau