$re = '/(<Contract)(.*)(Contract>)/is';
$str = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Records xmlns="http://www.datapump.cig.com">
<Contract phaseId="4" operation="2">
<General>
<ContractCode>8848</ContractCode>
<DateOfSignature>2009-09-08</DateOfSignature>
<CreditPurpose id="20"/>
<NegativeStatus id="4"/>
<ApplicationDate>2009-09-08</ApplicationDate>
<StartDate>2009-09-08</StartDate>
<ExpectedEndDate>2011-03-31</ExpectedEndDate>
<Subjects>
<Subject roleId="1">
<Entity>
<Individual gender="1">
<FirstName>
<Text language="uk-UA">украинÑкий</Text>
</FirstName>
<Surname>
<Text language="uk-UA">Первый</Text>
</Surname>
<FathersName>
<Text language="uk-UA">контрагент</Text>
</FathersName>
<Classification id="1"/>
<DateOfBirth>1980-12-06</DateOfBirth>
<Residency id="1"/>
<Citizenship code="UA"/>
<MaritalStatus id="2"/>
<Identifications>
<Identification typeId="2">
<Number>2554209876</Number>
</Identification>
<Identification typeId="4">
<Number>ВЦ620997</Number>
<IssueDate>1997-04-01</IssueDate>
<Authority language="uk-UA">ДебальцевÑкий ГОУМВД Украины в Донецкой облаÑти</Authority>
</Identification>
<Identification typeId="1">
<Number>2554209876</Number>
</Identification>
</Identifications>
<Addresses>
<Address typeId="2">
<Street>
<Text language="uk-UA">м. Kharkov, вул. Street, буд. 1, кв. 1</Text>
</Street>
</Address>
</Addresses>
</Individual>
</Entity>
</Subject>
</Subjects>
</General>
<Type>
<Credit paymentPeriodId="9" paymentMethodId="6">
<CreditLimit currency="USD">7800.0</CreditLimit>
<Records>
<Record accountingDate="2011-04-20">
<CreditUsage id="3"/>
<ResidualAmount currency="USD">7800.0</ResidualAmount>
<OverdueAmount currency="USD">0.0</OverdueAmount>
</Record>
</Records>
</Credit>
</Type>
</Contract>';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php