diff --git a/icu4c/source/common/putil.c b/icu4c/source/common/putil.c
index 459dbe34cb..e86e3c66c2 100644
--- a/icu4c/source/common/putil.c
+++ b/icu4c/source/common/putil.c
@@ -58,6 +58,7 @@
 #include "unicode/utypes.h"
 #include "unicode/putil.h"
 #include "unicode/ustring.h"
+#include "putilimp.h"
 #include "uassert.h"
 #include "umutex.h"
 #include "cmemory.h"
@@ -1897,7 +1898,6 @@ int_getDefaultCodepage()
     char *name = NULL;
     char *euro = NULL;
     const char *localeName = NULL;
-    const char *defaultTable = NULL;
 
     uprv_memset(codesetName, 0, sizeof(codesetName));
 
diff --git a/icu4c/source/common/resbund_cnv.cpp b/icu4c/source/common/resbund_cnv.cpp
index a643161272..b7eddbf3fa 100644
--- a/icu4c/source/common/resbund_cnv.cpp
+++ b/icu4c/source/common/resbund_cnv.cpp
@@ -44,7 +44,7 @@ ResourceBundle::constructForLocale(const UnicodeString& path,
 {
     char name[300];
 
-    if(path.length() >= sizeof(name)) {
+    if(path.length() >= (int32_t)sizeof(name)) {
         fResource = NULL;
         error = U_ILLEGAL_ARGUMENT_ERROR;
     } else if(!path.isEmpty()) {
diff --git a/icu4c/source/common/unames.c b/icu4c/source/common/unames.c
index 1ff98ec7f7..d53f77c5e5 100644
--- a/icu4c/source/common/unames.c
+++ b/icu4c/source/common/unames.c
@@ -24,6 +24,7 @@
 #include "cstring.h"
 #include "ucln_cmn.h"
 #include "udataswp.h"
+#include "uprops.h"
 
 /* prototypes ------------------------------------------------------------- */
 
diff --git a/icu4c/source/i18n/casetrn.cpp b/icu4c/source/i18n/casetrn.cpp
index 3920e7b593..39469edb3b 100644
--- a/icu4c/source/i18n/casetrn.cpp
+++ b/icu4c/source/i18n/casetrn.cpp
@@ -144,7 +144,9 @@ void CaseMapTransliterator::handleTransliterate(Replaceable& text,
         return;
     }
 
-    UCaseContext csc={ &text };
+    UCaseContext csc;
+    uprv_memset(&csc, 0, sizeof(csc));
+    csc.p = &text;
     csc.start = offsets.contextStart;
     csc.limit = offsets.contextLimit;
 
diff --git a/icu4c/source/i18n/dcfmtsym.cpp b/icu4c/source/i18n/dcfmtsym.cpp
index 46f43aac80..74d658d7d4 100644
--- a/icu4c/source/i18n/dcfmtsym.cpp
+++ b/icu4c/source/i18n/dcfmtsym.cpp
@@ -154,7 +154,6 @@ DecimalFormatSymbols::initialize(const Locale& loc, UErrorCode& status,
             int32_t numberElementsStrLen[kFormatSymbolCount];
             int32_t i = 0;
             for(i = 0; i<numberElementsLength; i++) {
-                int32_t len = 0;
                 numberElements[i] = ures_getStringByIndex(numberElementsRes, i, &numberElementsStrLen[i], &status);
             }
 
@@ -209,9 +208,13 @@ DecimalFormatSymbols::initialize(const UChar** numberElements, int32_t *numberEl
         {kPlusSignSymbol, 11},
         {kMonetarySeparatorSymbol, 0}
     };
+    static const int32_t TYPE_MAPPING_LEN = (int32_t)(sizeof(TYPE_MAPPING)/sizeof(TYPE_MAPPING[0]));
     int32_t idx;
+    if (numberElementsLength > TYPE_MAPPING_LEN) {
+        numberElementsLength = TYPE_MAPPING_LEN;
+    }
 
-    for (idx = 0; idx < (int32_t)(sizeof(TYPE_MAPPING)/sizeof(TYPE_MAPPING[0])); idx++) {
+    for (idx = 0; idx < numberElementsLength; idx++) {
         fSymbols[TYPE_MAPPING[idx][0]].setTo(TRUE, numberElements[TYPE_MAPPING[idx][1]], numberElementsStrLen[TYPE_MAPPING[idx][1]]);
     }
 
diff --git a/icu4c/source/i18n/titletrn.cpp b/icu4c/source/i18n/titletrn.cpp
index 57db64c1fd..dd3375b900 100644
--- a/icu4c/source/i18n/titletrn.cpp
+++ b/icu4c/source/i18n/titletrn.cpp
@@ -107,7 +107,9 @@ void TitlecaseTransliterator::handleTransliterate(
     // Convert things after a cased character toLower; things
     // after an uncased, non-case-ignorable character toTitle.  Case-ignorable
     // characters are copied directly and do not change the mode.
-    UCaseContext csc={ &text };
+    UCaseContext csc;
+    uprv_memset(&csc, 0, sizeof(csc));
+    csc.p = &text;
     csc.start = offsets.contextStart;
     csc.limit = offsets.contextLimit;