diff --git a/packages/api-derive/src/staking/erasPrefs.ts b/packages/api-derive/src/staking/erasPrefs.ts
index 826737ed1e..215d908626 100644
--- a/packages/api-derive/src/staking/erasPrefs.ts
+++ b/packages/api-derive/src/staking/erasPrefs.ts
@@ -13,9 +13,7 @@ import { StorageKey } from '@polkadot/types';
 
 import { memo } from '../util';
 
-type KeysAndPrefs = [StorageKey, ValidatorPrefs][];
-
-function mapPrefs (era: EraIndex, all: KeysAndPrefs): DeriveEraPrefs {
+function mapPrefs (era: EraIndex, all: [StorageKey, ValidatorPrefs][]): DeriveEraPrefs {
   const validators: DeriveEraValPrefs = {};
 
   all.forEach(([key, prefs]): void => {
diff --git a/packages/api-derive/src/staking/erasSlashes.ts b/packages/api-derive/src/staking/erasSlashes.ts
new file mode 100644
index 0000000000..dda2bb2953
--- /dev/null
+++ b/packages/api-derive/src/staking/erasSlashes.ts
@@ -0,0 +1,55 @@
+// Copyright 2017-2020 @polkadot/api-derive authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { ApiInterfaceRx } from '@polkadot/api/types';
+import { BalanceOf, EraIndex, Perbill } from '@polkadot/types/interfaces';
+import { ITuple } from '@polkadot/types/types';
+import { DeriveEraSlashes, DeriveEraValSlash } from '../types';
+
+import BN from 'bn.js';
+import { Observable, combineLatest, of } from 'rxjs';
+import { map, switchMap } from 'rxjs/operators';
+import { Option, StorageKey } from '@polkadot/types';
+
+import { memo } from '../util';
+
+function mapSlashes (era: EraIndex, noms: [StorageKey, Option<BalanceOf>][], vals: [StorageKey, Option<ITuple<[Perbill, BalanceOf]>>][]): DeriveEraSlashes {
+  const nominators: DeriveEraValSlash = {};
+  const validators: DeriveEraValSlash = {};
+
+  noms.forEach(([key, optBalance]): void => {
+    nominators[key.args[1].toString()] = optBalance.unwrap();
+  });
+
+  vals.forEach(([key, optRes]): void => {
+    validators[key.args[1].toString()] = optRes.unwrapOrDefault()[1];
+  });
+
+  return { era, nominators, validators };
+}
+
+export function eraSlashes (api: ApiInterfaceRx): (era: EraIndex) => Observable<DeriveEraSlashes> {
+  return memo((era: EraIndex): Observable<DeriveEraSlashes> =>
+    combineLatest([
+      api.query.staking.nominatorSlashInEra.entries(era),
+      api.query.staking.validatorSlashInEra.entries(era)
+    ]).pipe(
+      map(([noms, vals]) => mapSlashes(era, noms, vals))
+    )
+  );
+}
+
+export function erasSlashes (api: ApiInterfaceRx): (withActive?: boolean | BN | number) => Observable<DeriveEraSlashes[]> {
+  return memo((withActive?: boolean | BN | number): Observable<DeriveEraSlashes[]> =>
+    api.derive.staking.erasHistoric(withActive).pipe(
+      switchMap((eras): Observable<DeriveEraSlashes[]> =>
+        eras.length
+          ? combineLatest(
+            eras.map((era) => api.derive.staking.eraSlashes(era))
+          )
+          : of([])
+      )
+    )
+  );
+}
diff --git a/packages/api-derive/src/staking/index.ts b/packages/api-derive/src/staking/index.ts
index 5f3967ef46..ebf4fc5859 100644
--- a/packages/api-derive/src/staking/index.ts
+++ b/packages/api-derive/src/staking/index.ts
@@ -8,6 +8,7 @@ export * from './erasHistoric';
 export * from './erasPoints';
 export * from './erasPrefs';
 export * from './erasRewards';
+export * from './erasSlashes';
 export * from './controllers';
 export * from './electedInfo';
 export * from './overview';
@@ -15,4 +16,5 @@ export * from './query';
 export * from './stakerExposure';
 export * from './stakerPoints';
 export * from './stakerRewards';
+export * from './stakerSlashes';
 export * from './validators';
diff --git a/packages/api-derive/src/staking/stakerSlashes.ts b/packages/api-derive/src/staking/stakerSlashes.ts
new file mode 100644
index 0000000000..d0d24415b4
--- /dev/null
+++ b/packages/api-derive/src/staking/stakerSlashes.ts
@@ -0,0 +1,28 @@
+// Copyright 2017-2020 @polkadot/api-derive authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { ApiInterfaceRx } from '@polkadot/api/types';
+import { DeriveStakerSlashes } from '../types';
+
+import BN from 'bn.js';
+import { Observable } from 'rxjs';
+import { map } from 'rxjs/operators';
+
+import { memo } from '../util';
+
+export function stakerSlashes (api: ApiInterfaceRx): (accountId: Uint8Array | string, withActive?: boolean | BN | number) => Observable<DeriveStakerSlashes[]> {
+  return memo((accountId: Uint8Array | string, withActive?: boolean | BN | number): Observable<DeriveStakerSlashes[]> => {
+    const stakerId = api.registry.createType('AccountId', accountId).toString();
+
+    return api.derive.staking.erasSlashes(withActive).pipe(
+      map((slashes): DeriveStakerSlashes[] =>
+        slashes.map(({ era, nominators, validators }): DeriveStakerSlashes => ({
+          era,
+          isValidator: !!validators[stakerId],
+          total: nominators[stakerId] || validators[stakerId] || api.registry.createType('Balance')
+        }))
+      )
+    );
+  });
+}
diff --git a/packages/api-derive/src/staking/types.ts b/packages/api-derive/src/staking/types.ts
index 5a2bb6ec47..7492230834 100644
--- a/packages/api-derive/src/staking/types.ts
+++ b/packages/api-derive/src/staking/types.ts
@@ -9,6 +9,8 @@ export type DeriveEraValPoints = Record<string, RewardPoint>;
 
 export type DeriveEraValPrefs = Record<string, ValidatorPrefs>;
 
+export type DeriveEraValSlash = Record<string, Balance>;
+
 export interface DeriveEraPoints {
   era: EraIndex;
   eraPoints: RewardPoint;
@@ -25,6 +27,12 @@ export interface DeriveEraRewards {
   eraReward: Balance;
 }
 
+export interface DeriveEraSlashes {
+  era: EraIndex;
+  nominators: DeriveEraValSlash;
+  validators: DeriveEraValSlash;
+}
+
 export interface DeriveStakerPoints {
   era: EraIndex;
   eraPoints: RewardPoint;
@@ -58,6 +66,12 @@ export interface DeriveStakerReward {
   total: Balance;
 }
 
+export interface DeriveStakerSlashes {
+  era: EraIndex;
+  isValidator: boolean;
+  total: Balance;
+}
+
 export interface DerivedStakingElected {
   nextElected: AccountId[];
   info: DerivedStakingQuery[];