diff --git a/icu4c/source/aclocal.m4 b/icu4c/source/aclocal.m4
index 75cab770ac..adce4c3f48 100644
--- a/icu4c/source/aclocal.m4
+++ b/icu4c/source/aclocal.m4
@@ -72,7 +72,6 @@ powerpc*-*-linux*)
 *-dec-osf*) icu_cv_host_frag=mh-alpha-osf ;;
 *-*-nto*)	icu_cv_host_frag=mh-qnx ;;
 *-ncr-*)	icu_cv_host_frag=mh-mpras ;;
-*-sequent-*) 	icu_cv_host_frag=mh-ptx ;;
 *) 		icu_cv_host_frag=mh-unknown ;;
 esac
 		]
diff --git a/icu4c/source/common/umapfile.c b/icu4c/source/common/umapfile.c
index bb020fcd79..356e55ac32 100644
--- a/icu4c/source/common/umapfile.c
+++ b/icu4c/source/common/umapfile.c
@@ -1,7 +1,7 @@
 /*
 ******************************************************************************
 *
-*   Copyright (C) 1999-2005, International Business Machines
+*   Copyright (C) 1999-2006, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 ******************************************************************************/
@@ -49,7 +49,7 @@
 #   define MAP_IMPLEMENTATION MAP_WIN32
 
 /* ### Todo: properly auto detect mmap(). Until then, just add your platform here. */
-#elif U_HAVE_MMAP || defined(U_AIX) || defined(U_HPUX) || defined(OS390) || defined(PTX)
+#elif U_HAVE_MMAP || defined(U_AIX) || defined(U_HPUX) || defined(OS390)
     typedef size_t MemoryMap;
 
 #   define IS_MAP(map) ((map)!=0)
diff --git a/icu4c/source/config/mh-ptx b/icu4c/source/config/mh-ptx
deleted file mode 100644
index 0cba7dd64a..0000000000
--- a/icu4c/source/config/mh-ptx
+++ /dev/null
@@ -1,65 +0,0 @@
-## -*-makefile-*-
-## PTX-specific setup
-## Copyright (c) 1999-2004, International Business Machines Corporation and
-## others. All Rights Reserved.
-
-## Flags for position independent code
-SHAREDLIBCFLAGS = -KPIC
-SHAREDLIBCXXFLAGS = -KPIC
-SHAREDLIBCPPFLAGS = -DPIC
-
-## Commands to generate dependency files
-GEN_DEPS.c=	$(CC) -Kthread -DPTX -c $(DEFS) $(CPPFLAGS)
-GEN_DEPS.cc=	$(CXX) -M -DPTX $(DEFS) $(CPPFLAGS)
-
-## Commands to compile
-COMPILE.c=	$(CC) -Kthread -DPTX $(DEFS) $(CPPFLAGS) $(CFLAGS) -c
-COMPILE.cc=	$(CXX) -Kthread -DPTX $(DEFS) $(CPPFLAGS) $(CXXFLAGS) -c
-
-## Commands to link
-#LINK.c=		$(CC) $(DEFS) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)
-LINK.c=		$(CXX) $(DEFS) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -lm -lgen
-LINK.cc=	$(CXX) $(DEFS) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -lm -lgen
-
-## Commands to make a shared library
-SHLIB.c=	$(CC) $(DEFS) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -DPTX -G
-SHLIB.cc=	$(CXX) $(DEFS) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -DPTX -G
-
-## Compiler switch to embed a runtime search path
-LD_RPATH=	-R	
-LD_RPATH_PRE=
-
-## Versioned target for a shared library.
-FINAL_SO_TARGET = $(SO_TARGET)
-MIDDLE_SO_TARGET = 
-
-## Shared object suffix
-SO=		so
-## Non-shared intermediate object suffix
-STATIC_O = ao
-
-## Compilation rules
-%.$(STATIC_O): $(srcdir)/%.c
-	$(COMPILE.c) $(STATICCPPFLAGS) $(STATICCFLAGS) -o $@ $<
-%.o: $(srcdir)/%.c
-	$(COMPILE.c) $(DYNAMICCPPFLAGS) $(DYNAMICCFLAGS) -o $@ $<
-
-%.$(STATIC_O): $(srcdir)/%.cpp
-	$(COMPILE.cc) $(STATICCPPFLAGS) $(STATICCXXFLAGS) -o $@ $<
-%.o: $(srcdir)/%.cpp
-	$(COMPILE.cc) $(DYNAMICCPPFLAGS) $(DYNAMICCXXFLAGS) -o $@ $<
-
-## Dependency rules
-%.d : $(srcdir)/%.c
-	@echo "generating dependency information for $<"
-	@$(SHELL) -ec '$(GEN_DEPS.c) $< \
-		| sed '\''s/\($*\)\.o[ :]*/\1.o $@ : /g'\'' > $@; \
-		[ -s $@ ] || rm -f $@'
-
-%.d : $(srcdir)/%.cpp
-	@echo "generating dependency information for $<"
-	@$(SHELL) -ec '$(GEN_DEPS.cc) -o $@ $< \
-		| sed '\''s/\($*\)\.o[ :]*/\1.o $@ : /g'\'' > $@; \
-		[ -s $@ ] || rm -f $@'
-
-## End Ptx-specific setup
diff --git a/icu4c/source/configure b/icu4c/source/configure
index 65be738363..097a8e51e8 100755
--- a/icu4c/source/configure
+++ b/icu4c/source/configure
@@ -3402,7 +3402,6 @@ powerpc*-*-linux*)
 *-dec-osf*) icu_cv_host_frag=mh-alpha-osf ;;
 *-*-nto*)	icu_cv_host_frag=mh-qnx ;;
 *-ncr-*)	icu_cv_host_frag=mh-mpras ;;
-*-sequent-*) 	icu_cv_host_frag=mh-ptx ;;
 *) 		icu_cv_host_frag=mh-unknown ;;
 esac
 
@@ -7616,7 +7615,6 @@ case "${host}" in
 	*-*-beos)		platform=U_BEOS ;;
 	*-*-irix*)		platform=U_IRIX ;;
 	*-ncr-*)		platform=U_MPRAS ;;
-	*-sequent-*)	platform=PTX ;;
 	*) 		platform=U_UNKNOWN_PLATFORM ;;
 esac
 
@@ -7634,7 +7632,6 @@ case "${host}" in
 	*-*-hpux*) 	ld_rpath_suf=":" ;;
 	*-*ibm-openedition*|*-*-os390*)	ld_rpath_suf="" ;;
 	*-*-os400*)	ld_rpath_suf=" " ;;
-	*-sequent-*)	ld_rpath_suf="" ;;
 	*-*-irix*)      ld_rpath_suf=" " ;;
 	*) 		ld_rpath_suf="" ;;
 esac
diff --git a/icu4c/source/configure.in b/icu4c/source/configure.in
index eface5e2e0..4d2a7d3bed 100644
--- a/icu4c/source/configure.in
+++ b/icu4c/source/configure.in
@@ -913,7 +913,6 @@ case "${host}" in
 	*-*-beos)		platform=U_BEOS ;;
 	*-*-irix*)		platform=U_IRIX ;;
 	*-ncr-*)		platform=U_MPRAS ;;
-	*-sequent-*)	platform=PTX ;;
 	*) 		platform=U_UNKNOWN_PLATFORM ;;
 esac
 AC_SUBST(ICUDATA_CHAR)
@@ -932,7 +931,6 @@ case "${host}" in
 	*-*-hpux*) 	ld_rpath_suf=":" ;;
 	*-*ibm-openedition*|*-*-os390*)	ld_rpath_suf="" ;;
 	*-*-os400*)	ld_rpath_suf=" " ;;
-	*-sequent-*)	ld_rpath_suf="" ;;
 	*-*-irix*)      ld_rpath_suf=" " ;;
 	*) 		ld_rpath_suf="" ;;
 esac