To add a new LDAP entry, first bind as a user with permissions to add: ldap.DN = "DOMAIN\\Administrator"; ldap.Password = "admin"; ldap.Bind(); Next, specify the new DN you'd like to add, and specify all the attributes that will be required in order to add this new entry to the server. Which attributes are required depend on the schema. For Active Directory, a typical user DN add might look like this: ldap.DN = "cn=NewUser,cn=Users,dc=DOMAIN"; ldap.Attributes.Add(new LDAPAttribute("objectClass", "top")); ldap.Attributes.Add(new LDAPAttribute("", "person")); ldap.Attributes.Add(new LDAPAttribute("", "organizationalPerson")); ldap.Attributes.Add(new LDAPAttribute("", "inetorgperson")); ldap.Add(); Next, you can go back and use the Modify method to add other attributes to this entry.