Ok, I understand. Now I have another problem. Here is my revised query:

CREATE PROCEDURE sproc_GetContacts
	@FName VARCHAR(50) = NULL,
	@LName VARCHAR(50) = NULL,
	@IsMale BIT = NULL,
	@IsFemale BIT = NULL,
	@Age VARCHAR(3) = NULL,
	@Address_Number NVARCHAR(50) = NULL,
	@Street NVARCHAR(50) = NULL,
	@City NVARCHAR(50) = NULL,
	@State CHAR(2) = NULL,
	@Zip VARCHAR(5) = NULL,
	@IsDemocrat BIT = NULL,
	@IsRepublican BIT = NULL,
	@IsIndependent BIT = NULL
	
AS

	SET @FName = UPPER(@FName)
	SET @LName = UPPER(@LName)
	SET @Age = UPPER(@Age)
	SET @Street = UPPER(@Street)
	SET @City = UPPER(@City)
	SET @State = UPPER(@State)

	DECLARE @Sql NVARCHAR(2000)
	DECLARE @Where NVARCHAR(1000) = ''
	SET @Sql = 'SELECT	VoterID, FName, LName, Sex, Age, Address_Number, Street, City, State, Zip, Party FROM tblCamp_CT '
	
	IF @FName IS NOT NULL
		SET @Where = @Where + ' AND FName = @_FName '

	IF @LName IS NOT NULL
		SET @Where = @Where + 'AND LName = @_LName '

	IF @IsMale IS NOT NULL AND @IsMale = 1
		SET @Where = @Where + 'AND Sex = ''M'' '

	IF @IsFemale IS NOT NULL AND @IsFemale = 1
		SET @Where = @Where + 'AND Sex = ''F'' '

	IF @Age IS NOT NULL
		SET @Where = @Where + 'AND Age = @_Age '

	IF @Address_Number IS NOT NULL
		SET @Where = @Where + 'AND Address_Number = @_Address_Number '

	IF @Street IS NOT NULL
		SET @Where = @Where + 'AND Street = @_Street '

	IF @City IS NOT NULL
		SET @Where = @Where + 'AND City = @_City '

	IF @State IS NOT NULL
		SET @Where = @Where + 'AND State = @_State '

	IF @Zip IS NOT NULL
		SET @Where = @Where + 'AND Zip = @_Zip '

	IF @IsDemocrat IS NOT NULL AND @IsDemocrat = 1
		SET @Where = @Where + 'AND Party = ''D'' '
	
	IF @IsRepublican IS NOT NULL AND @IsRepublican = 1
		SET @Where = @Where + 'AND Party = ''R'' '
	
	IF @IsIndependent IS NOT NULL AND @IsIndependent = 1
		SET @Where = @Where + 'AND Party = ''U'' '
	
	IF LEN(@Where) > 0 
		SET @Sql = @Sql + 'WHERE ' + RIGHT(@Where, LEN(@Where)-3)
	
	SET @Sql = @Sql + ' ORDER BY FName, LName'

	EXEC sp_executesql @SQL,
	N'@_FName VARCHAR(50),
	 @_LName VARCHAR(50),
	 @_IsMale BIT,
	 @_IsFemale BIT,
	 @_Age VARCHAR(3),
	 @_Address_Number NVARCHAR(50),
	 @_Street NVARCHAR(50),
	 @_City NVARCHAR(50),
	 @_State CHAR(2),
	 @_Zip VARCHAR(5),
	 @_IsDemocrat BIT,
	 @_IsRepublican BIT,
	 @_IsIndependent BIT',
	@_FName = @FName,
	@_LName = @LName,
	@_IsMale = @IsMale,
	@_IsFemale = @IsFemale,
	@_Age = @Age,
	@_Address_Number = @Address_Number,
	@_Street = @Street,
	@_City = @City,
	@_State = @State,
	@_Zip = @Zip,
	@_IsDemocrat = @IsDemocrat,
	@_IsRepublican = @IsRepublican,
	@_IsIndependen = @IsIndependent

When I run this

EXEC sproc_GetContacts @FName = 'WILLIAM', @LName = 'BRAY', @IsDemocrat=1, @IsRepublican=1, @IsIndependent=1

I get

The parameterized query '(@_FName VARCHAR(50),
 @_LName VARCHAR(50),
 @_IsMale BIT,
 @' expects the parameter '@_IsIndependent', which was not supplied.

The table has a column called 'Party', and if I passed in IsDemocrat, then any row with a 'D' in the Party field should be retured. Same for the IsRepublican or IsIndepdendent ('R' and 'U').

I understand what it's telling me - I just don't know how to correctly code this.

Can you point me in the rigt direction?

Thanks!