diff --git a/ruby.spec b/ruby.spec
index 9b07aa2..a4fecc0 100644
--- a/ruby.spec
+++ b/ruby.spec
@@ -94,10 +94,11 @@ Source6: abrt_prelude.rb
 Source8: rubygems.attr
 Source9: rubygems.req
 Source10: rubygems.prov
+Source11: rubygems.con
 # ABRT hoook test case.
-Source12: test_abrt.rb
+Source13: test_abrt.rb
 # SystemTap tests.
-Source13: test_systemtap.rb
+Source14: test_systemtap.rb
 
 # The load directive is supported since RPM 4.12, i.e. F21+. The build process
 # fails on older Fedoras.
@@ -599,6 +600,7 @@ mkdir -p %{buildroot}%{_rpmconfigdir}/fileattrs
 install -m 644 %{SOURCE8} %{buildroot}%{_rpmconfigdir}/fileattrs
 install -m 755 %{SOURCE9} %{buildroot}%{_rpmconfigdir}
 install -m 755 %{SOURCE10} %{buildroot}%{_rpmconfigdir}
+install -m 755 %{SOURCE11} %{buildroot}%{_rpmconfigdir}
 
 # Install custom operating_system.rb.
 mkdir -p %{buildroot}%{rubygems_dir}/rubygems/defaults
@@ -726,10 +728,10 @@ touch abrt.rb
 
 # Check if abrt hook is required (RubyGems are disabled by default when using
 # runruby, so re-enable them).
-make runruby TESTRUN_SCRIPT="--enable-gems %{SOURCE12}"
+make runruby TESTRUN_SCRIPT="--enable-gems %{SOURCE13}"
 
 # Check if systemtap is supported.
-%{?with_systemtap:make runruby TESTRUN_SCRIPT=%{SOURCE13}}
+%{?with_systemtap:make runruby TESTRUN_SCRIPT=%{SOURCE14}}
 
 DISABLE_TESTS=""
 
@@ -960,6 +962,7 @@ make check TESTS="-v $DISABLE_TESTS"
 %{_rpmconfigdir}/fileattrs/rubygems.attr
 %{_rpmconfigdir}/rubygems.req
 %{_rpmconfigdir}/rubygems.prov
+%{_rpmconfigdir}/rubygems.con
 
 %files -n rubygem-rake
 %{_bindir}/rake
@@ -1064,6 +1067,7 @@ make check TESTS="-v $DISABLE_TESTS"
 - Drop obsolete ldconfig scriptlets.
 - Add GMP dependency.
 - Use 'with' operator in RPM dependency generator.
+- Add conflicts RPM generator.
 
 * Fri Feb 09 2018 Fedora Release Engineering <releng@fedoraproject.org> - 2.5.0-89
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild
diff --git a/rubygems.attr b/rubygems.attr
index f033d43..5793bf7 100644
--- a/rubygems.attr
+++ b/rubygems.attr
@@ -1,5 +1,6 @@
 %__rubygems_requires	%{_rpmconfigdir}/rubygems.req
 %__rubygems_provides	%{_rpmconfigdir}/rubygems.prov
+%__rubygems_conflicts	%{_rpmconfigdir}/rubygems.con
 # In non-gem packages, the %%{gem_name} macro is not available and the macro
 # stays unexpanded which leads to "invalid regex" error (rhbz#1154067).
 %__rubygems_path	^%{?gem_name:%{gem_spec}}%{!?gem_name:this_should_never_match_anything}$
diff --git a/rubygems.con b/rubygems.con
new file mode 100644
index 0000000..1a99ed0
--- /dev/null
+++ b/rubygems.con
@@ -0,0 +1,52 @@
+#!/usr/bin/ruby
+
+require 'rubygems/package'
+
+module RubyGemsReq
+  module Helpers
+    # Keep only '!=' requirements.
+    def self.conflicts(requirements)
+      conflicts = requirements.select {|r| r.first == '!='}
+    end
+
+    # Converts Gem::Requirement into array of requirements strings compatible
+    # with RPM .spec file.
+    def self.requirement_versions_to_rpm(requirement)
+      self.conflicts(requirement.requirements).map do |op, version|
+        version == Gem::Version.new(0) ? "" : "= #{version}"
+      end
+    end
+  end
+
+  # Report conflicting gem dependencies including their version.
+  def self.gem_depenencies(specification)
+    specification.runtime_dependencies.each do |dependency|
+      conflict_strings = Helpers::requirement_versions_to_rpm(dependency.requirement).map do |requirement|
+        requirement_string = "rubygem(#{dependency.name}) #{requirement}"
+      end
+      if conflict_strings.length > 0
+        conflict_string = conflict_strings.join(' with ')
+        conflict_string.prepend('(').concat(')') if conflict_strings.length > 1
+        puts conflict_string
+      end
+    end
+  end
+
+  # Reports all conflicts specified by all provided .gemspec files.
+  def self.conflicts
+    while filename = gets
+      filename.strip!
+      begin
+        specification = Gem::Specification.load filename
+
+        gem_depenencies(specification)
+      rescue => e
+        # Ignore all errors.
+      end
+    end
+  end
+end
+
+if __FILE__ == $0
+  RubyGemsReq::conflicts
+end
diff --git a/rubygems.req b/rubygems.req
index 8e032c9..6868bdd 100644
--- a/rubygems.req
+++ b/rubygems.req
@@ -11,11 +11,11 @@ module RubyGemsReq
         when '~>'
           expand_pessimistic_requirement(r)
         when '!='
-          expand_not_equal_requirement(r)
+          []
         else
           [r]
         end
-      end
+      end.reject {|r| r.empty? }
     end
 
     # Expands the pessimistic version operator '~>' into equivalent '>=' and
@@ -25,12 +25,6 @@ module RubyGemsReq
       return ['>=', requirement.last], ['<', next_version]
     end
 
-    # Expands the not equal version operator '!=' into equivalent '<' and
-    # '>' pair.
-    def self.expand_not_equal_requirement(requirement)
-      return ['<', requirement.last], ['>', requirement.last]
-    end
-
     # Converts Gem::Requirement into array of requirements strings compatible
     # with RPM .spec file.
     def self.requirement_versions_to_rpm(requirement)